def remove_child_family(self, family_id=None, child_id=None):
pass<EOL>
Removes a child from a family.

        arg:    family_id (osid.id.Id): the ``Id`` of a family
        arg:    child_id (osid.id.Id): the ``Id`` of the new child
        raise:  NotFound - ``family_id`` not a parent of ``child_id``
        raise:  NullArgument - ``family_id`` or ``child_id`` is ``null``
        raise:  OperationFailed - unable to complete request
        raise:  PermissionDenied - authorization failure
        *compliance: mandatory -- This method must be implemented.*