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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 is_feeder(self, team_id=None):
 """Ensure ther resource has the role FEEDER."""

        if team_id is None:
            return self._is_feeder
        team_id = uuid.UUID(str(team_id))
        if team_id not in self.teams_ids:
            return False
        return self.teams[team_id]['role'] == 'FEEDER'