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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_parent_of_objective(self, id_=None, objective_id=None):
 """Tests if an Id is a direct parent of an objective. arg: id (osid.id.Id):
 an Id arg: objective_id (osid.id.Id):
 the Id of an objective return: (boolean) - true if this id is a parent of objective_id, false otherwise raise: NotFound - objective_id is not found raise: NullArgument - id or objective_id is null raise: OperationFailed - unable to complete request raise: PermissionDenied - authorization failure compliance: mandatory - This method must be implemented. implementation notes: If id not found return false. """

        if id_ is None or objective_id is None:
            raise NullArgument()
        return id_ in list(self.get_parent_objective_ids(objective_id))