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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 revoke_membership(self, username):
 """Revoke this user's team membership. :param str username: (required), name of the team member :returns: bool """

        url = self._build_url('memberships', username, base_url=self._api)
        return self._boolean(self._delete(url), 204, 404)