@utilities.arguments_not_none<EOL><INDENT>def get_objective_bank_nodes(self, objective_bank_id, ancestor_levels, descendant_levels, include_siblings):<DEDENT>
<EOL>return objects.ObjectiveBankNode(self.get_objective_bank_node_ids(<EOL>objective_bank_id=objective_bank_id,<EOL>ancestor_levels=ancestor_levels,<EOL>descendant_levels=descendant_levels,<EOL>include_siblings=include_siblings)._my_map, runtime=self._runtime, proxy=self._proxy)<EOL>
Gets a portion of the hierarchy for the given objective bank.

        arg:    objective_bank_id (osid.id.Id): the ``Id`` to query
        arg:    ancestor_levels (cardinal): the maximum number of
                ancestor levels to include. A value of 0 returns no
                parents in the node.
        arg:    descendant_levels (cardinal): the maximum number of
                descendant levels to include. A value of 0 returns no
                children in the node.
        arg:    include_siblings (boolean): ``true`` to include the
                siblings of the given node, ``false`` to omit the
                siblings
        return: (osid.learning.ObjectiveBankNode) - an objective bank
                node
        raise:  NotFound - ``objective_bank_id`` not found
        raise:  NullArgument - ``objective_bank_id`` is ``null``
        raise:  OperationFailed - unable to complete request
        raise:  PermissionDenied - authorization failure
        *compliance: mandatory -- This method must be implemented.*