The expression $this->_data; of type array|Cake\ORM\Entity adds the type Cake\ORM\Entity to the return on line 66 which is incompatible with the return type documented by Core\Utility\Macros::get of type array.
The expression $this->_data of type array|object<Cake\ORM\Entity> is not guaranteed to be traversable. How about adding an additional type check?
There are different options of fixing this problem.
If you want to be on the safe side, you can add an additional type-check:
$collection=json_decode($data,true);if(!is_array($collection)){thrownew\RuntimeException('$collection must be an array.');}foreach($collectionas$item){/** ... */}
If you are sure that the expression is traversable, you might want to add a
doc comment cast to improve IDE auto-completion and static analysis: