@Nullable
  private static PyType getStringLiteralType(@NotNull PsiElement element, @NotNull Context context) {
    if (element instanceof PyStringLiteralExpression) {
      final String contents = ((PyStringLiteralExpression)element).getStringValue();
      return Ref.deref(getStringBasedType(contents, element, context));
    }
    return null;
  }
@Nullable
  private static PyType getStringLiteralType(@NotNull PsiElement element, @NotNull Context context)