@Nullable
  public static Ref<QualifiedName> getAssignedReferenceQualifiedName(@NotNull PyTargetExpression psi) {
    final PyTargetExpressionStub stub = psi.getStub();
    if (stub != null) {
      if (stub.getInitializerType() == PyTargetExpressionStub.InitializerType.ReferenceExpression) {
        return Ref.create(stub.getInitializer());
      }
      return null;
    }
    final PyExpression value = psi.findAssignedValue();
    return value instanceof PyReferenceExpression ? Ref.create(((PyReferenceExpression)value).asQualifiedName()) : null;
  }
@Nullable
  public static Ref<QualifiedName> getAssignedReferenceQualifiedName(@NotNull PyTargetExpression psi)