@Nullable
  private static PyType wrapInAsyncGeneratorType(@Nullable PyType elementType, @NotNull PsiElement anchor) {
    final PyClass asyncGenerator = PyPsiFacade.getInstance(anchor.getProject()).createClassByQName(ASYNC_GENERATOR, anchor);
    return asyncGenerator != null ? new PyCollectionTypeImpl(asyncGenerator, false, Arrays.asList(elementType, null)) : null;
  }
@Nullable
  private static PyType wrapInAsyncGeneratorType(@Nullable PyType elementType, @NotNull PsiElement anchor)