@Nullable
  private static Boolean isUnionCallable(@NotNull final PyUnionType type) {
    for (final PyType member : type.getMembers()) {
      final Boolean callable = isCallable(member);
      if (callable == null) {
        return null;
      }
      if (callable) {
        return true;
      }
    }
    return false;
  }
@Nullable
  private static Boolean isUnionCallable(@NotNull final PyUnionType type)