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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 get_child_families(self, family_id):
 """Gets the child families of the given ``id``. arg: family_id (osid.id.Id):
 the ``Id`` of the ``Family`` to query return: (osid.relationship.FamilyList) - the child families of the ``id`` raise: NotFound - a ``Family`` identified by ``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.* """

        # Implemented from template for
        # osid.resource.BinHierarchySession.get_child_bins
        if self._catalog_session is not None:
            return self._catalog_session.get_child_catalogs(catalog_id=family_id)
        return FamilyLookupSession(
            self._proxy,
            self._runtime).get_families_by_ids(
                list(self.get_child_family_ids(family_id)))