@Nullable
  private static PsiElement findProvidedReferenceAndResolve(@NotNull final PsiElement sourceElement) {
    for (final PsiReference reference : sourceElement.getReferences()) {
      if (reference instanceof PyUserInitiatedResolvableReference) {
        final PsiElement element = ((PyUserInitiatedResolvableReference)reference).userInitiatedResolve();
        if (element != null && element != sourceElement) {
          return element;
        }
      }
    }
    return null;
  }
@Nullable
  private static PsiElement findProvidedReferenceAndResolve(@NotNull final PsiElement sourceElement)