private boolean hasInheritors(@NotNull PyFunction function) {
      final Boolean cached = myHasInheritors.get(function);
      if (cached != null) {
        return cached;
      }
      final boolean result = PyOverridingMethodsSearch.search(function, true).findFirst() != null;
      myHasInheritors.put(function, result);
      return result;
    }
private boolean hasInheritors(@NotNull PyFunction function)