static <A, B> Map<A, B> unwrapSynchronizedMap(Map<A, B> map) {
  S name = className(map);
  if (eqOneOf(name,
    "java.util.Collections$SynchronizedMap",
    "java.util.Collections$SynchronizedSortedMap",
    "java.util.Collections$SynchronizedNavigableMap"))
    ret (Map) get(map, 'm);
  ret map;
}