@Nullable
  static PyStringLiteralExpression getEffectiveDocStringExpression(@NotNull PyDocStringOwner owner) {
    final PyStringLiteralExpression expression = owner.getDocStringExpression();
    if (expression != null) {
      return expression;
    }
    final PsiElement original = PyiUtil.getOriginalElement(owner);
    final PyDocStringOwner originalOwner = as(original, PyDocStringOwner.class);
    return originalOwner != null ? originalOwner.getDocStringExpression() : null;
  }
@Nullable
  static PyStringLiteralExpression getEffectiveDocStringExpression(@NotNull PyDocStringOwner owner)