Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
| 1 | <?php  | 
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| 19 | View Code Duplication | class Events extends ArrayCollection implements FromArrayInterface  | 
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| 20 | { | 
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| 21 | /**  | 
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| 22 | * @param Event $event  | 
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| 23 | *  | 
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| 24 | * @return $this  | 
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| 25 | */  | 
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| 26 | public function addEvent(Event $event)  | 
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| 32 | |||
| 33 | /**  | 
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| 34 | * @param Event $event  | 
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| 35 | */  | 
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| 36 | public function removeEvent(Event $event)  | 
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| 40 | |||
| 41 | /**  | 
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| 42 |      * {@inheritdoc} | 
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| 43 | */  | 
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| 44 | public static function fromArray(array $data)  | 
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| 54 | }  | 
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| 55 |