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                import pytest  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    4
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                @pytest.fixture  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    5
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                def subject():  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    6
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                    from so_magic.utils import Subject  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    7
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                    return Subject  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    8
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                    10
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                @pytest.fixture  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    11
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                def observer():  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    12
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                    from so_magic.utils import Observer  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    13
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                    return Observer  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    15
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                    16
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                def test_attrs_sanity():  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    import attr  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    19
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                    @attr.s  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    20
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                    class A:  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                        _observers = attr.ib(init=True, default=[])  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    23
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                    i1 = A()  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    24
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                    i2 = A()  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    assert id(i1._observers) == id(i2._observers)  # SOS  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    28
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                def test_attrs_sanity1():  | 
            
            
                                                                        
                            
            
                                    
            
            
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                    import attr  | 
            
            
                                                                        
                            
            
                                    
            
            
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                    @attr.s  | 
            
            
                                                                        
                            
            
                                    
            
            
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                    class A:  | 
            
            
                                                                        
                            
            
                                    
            
            
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                        _observers = attr.ib(init=True)  | 
            
            
                                                                        
                            
            
                                    
            
            
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                    34
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                        def add(self, *objects):  | 
            
            
                                                                        
                            
            
                                    
            
            
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                            self._observers.extend([_ for _ in objects])  | 
            
            
                                                                        
                            
            
                                    
            
            
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                    i1 = A([])  | 
            
            
                                                                        
                            
            
                                    
            
            
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                    i2 = A([])  | 
            
            
                                                                        
                            
            
                                    
            
            
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                    assert id(i1._observers) != id(i2._observers)  | 
            
            
                                                                        
                            
            
                                    
            
            
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                    i1.add('obs1') | 
            
            
                                                                        
                            
            
                                    
            
            
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                    assert i1._observers == ['obs1']  | 
            
            
                                                                        
                            
            
                                    
            
            
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                    assert i2._observers == []  | 
            
            
                                                                        
                            
            
                                    
            
            
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                    assert id(i1._observers) != id(i2._observers)  | 
            
            
                                                                        
                            
            
                                    
            
            
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                    @attr.s  | 
            
            
                                                                        
                            
            
                                    
            
            
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                    class B:  | 
            
            
                                                                        
                            
            
                                    
            
            
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                        _observers = attr.ib(init=True, default=attr.Factory(list))  | 
            
            
                                                                        
                            
            
                                    
            
            
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                    48
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                    i1 = B()  | 
            
            
                                                                        
                            
            
                                    
            
            
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                    49
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                    i2 = B()  | 
            
            
                                                                        
                            
            
                                    
            
            
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                    assert id(i1._observers) != id(i2._observers)  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    53
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                def test_observers_sanity_test1(subject):  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    subject1 = subject([])  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    subject2 = subject([])  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    assert hasattr(subject1, '_observers')  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    assert hasattr(subject2, '_observers')  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    assert id(subject1._observers) != id(subject2._observers)  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    60
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                    61
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                def test_observer_as_constructor(observer):  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    62
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                    with pytest.raises(TypeError) as instantiation_from_interface_error:  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                        observer_instance = observer()  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    assert "Can't instantiate abstract class Observer with abstract methods update" in str(instantiation_from_interface_error.value)  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    67
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                def test_scenario(subject, observer):  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    68
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                # The client code.  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    69
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                    70
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                    print("------ Scenario 1 ------\n") | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    71
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                    class ObserverA(observer):  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    72
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                        def update(self, a_subject) -> None:  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    73
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                            print("ObserverA: Reacted to the event") | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    74
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                    75
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                    s1 = subject([])  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    76
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                    # o1 = observer()  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    # s1.attach(o1)  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    79
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                    # business logic  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    80
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                    s1.state = 0  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    81
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                    s1.notify()  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    82
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                    83
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                    print("------ Scenario 2 ------\n") | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    84
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                    # example 2  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    85
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                    class Businessubject(subject):  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    86
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                    87
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                        def some_business_logic(self) -> None:  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    88
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                            """  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    89
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                            Usually, the subscription logic is only a fraction of what a Subject can  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    90
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                            really do. Subjects commonly hold some important business logic, that  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    91
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                            triggers a notification method whenever something important is about to  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    92
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                            happen (or after it).  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    93
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                            """  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                            print("\nSubject: I'm doing something important.") | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    95
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                            from random import randrange  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    96
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                            self._state = randrange(0, 10)  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                            print(f"Subject: My state has just changed to: {self._state}") | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    98
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                            self.notify()  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    99
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                    100
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                    class ObserverB(observer):  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    101
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                        def update(self, a_subject) -> None:  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    102
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                            if a_subject.state == 0 or a_subject.state >= 2:  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    103
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                                print("ObserverB: Reacted to the event") | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    104
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                    105
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                    s2 = Businessubject([])  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    106
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                    assert id(s1) != id(s2)  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    107
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                    assert id(s1._observers) != id(s2._observers)  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    108
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                    o1, o2 = ObserverA(), ObserverB()  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    109
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                    # s2.attach(o1)  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    110
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                    # s2.attach(o2)  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    111
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                    s2.add(o1, o2)  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    112
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                    # business logic  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    113
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                    print(s2._observers)  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    114
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                    s2.some_business_logic()  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    115
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                    s2.some_business_logic()  | 
            
            
                                                                                                            
                            
            
                                    
            
            
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                    116
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                    117
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                    s2.detach(o1)  | 
            
            
                                                                                                            
                                                                
            
                                    
            
            
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                    118
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                    s2.some_business_logic()  | 
            
            
                                                        
            
                                    
            
            
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                    119
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