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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def get_entity_by_tag(self, tag):
        '''
        Get entity by tag
        tag is a string that is the tag of the Entity.
        '''
        matching_entities = list(filter(lambda entity: entity.get_tag() == tag,
                                        self._entities))
        if matching_entities:
            return matching_entities[0]
        else:
            return None