@Override
  public void indexStub(@NotNull PyTargetExpressionStub stub, @NotNull IndexSink sink) {
    String name = stub.getName();
    if (name != null && PyUtil.getInitialUnderscores(name) == 0) {
      if (stub.getParentStub() instanceof PyFileStub) {
        sink.occurrence(PyVariableNameIndex.KEY, name);
        sink.occurrence(PyExportedModuleAttributeIndex.KEY, name);
      }
    }
    for (CustomTargetExpressionStubType stubType : getExtensions()) {
      stubType.indexStub(stub, sink);
    }
  }
@Override
  public void indexStub(@NotNull PyTargetExpressionStub stub, @NotNull IndexSink sink)