def get_child_family_ids(self, family_id=None):
pass<EOL>
Gets the child ``Ids`` of the given family.

        arg:    family_id (osid.id.Id): the ``Id`` to query
        return: (osid.id.IdList) - the children of the family
        raise:  NotFound - ``family_id`` is not found
        raise:  NullArgument - ``family_id`` is ``null``
        raise:  OperationFailed - unable to complete request
        raise:  PermissionDenied - authorization failure
        *compliance: mandatory -- This method must be implemented.*