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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 remove(self, obj):
 """ Removes a member from the collection. :param obj: Object to remove. Example: """

        activity = {
            "verb": "remove",
            "object": {
                "objectType": obj.object_type,
                "id": obj.id
            },
            "target": {
                "objectType": self.object_type,
                "id": self.id
            }
        }

        self._post_activity(activity)

        # Remove the cash so it's re-generated next time it's needed
        self._members = None