def METHOD_NAME(self):
    """
    Annotate the depth and number of child prefixes for each Prefix. Cast null VRF values to zero for
    comparison. (NULL != NULL).
    """
    return self.annotate(
        hierarchy_depth=RawSQL(
            'SELECT COUNT(DISTINCT U0."prefix") AS "c" '
            'FROM "ipam_prefix" U0 '
            'WHERE (U0."prefix" >> "ipam_prefix"."prefix" '
            'AND COALESCE(U0."vrf_id", 0) = COALESCE("ipam_prefix"."vrf_id", 0))',
            ()
        ),
        hierarchy_children=RawSQL(
            'SELECT COUNT(U1."prefix") AS "c" '
            'FROM "ipam_prefix" U1 '
            'WHERE (U1."prefix" << "ipam_prefix"."prefix" '
            'AND COALESCE(U1."vrf_id", 0) = COALESCE("ipam_prefix"."vrf_id", 0))',
            ()
        )
    )