@Nullable
  @Override
  default PyAstStringLiteralExpression getDocStringExpression() {
    final PsiElement parent = getParent();
    if (parent instanceof PyAstAssignmentStatement || parent instanceof PyAstTypeDeclarationStatement) {
      final PsiElement nextSibling = PyPsiUtilsCore.getNextNonCommentSibling(parent, true);
      if (nextSibling instanceof PyAstExpressionStatement) {
        final PyAstExpression expression = ((PyAstExpressionStatement)nextSibling).getExpression();
        if (expression instanceof PyAstStringLiteralExpression) {
          return (PyAstStringLiteralExpression)expression;
        }
      }
    }
    return null;
  }
@Nullable
  @Override
  default PyAstStringLiteralExpression getDocStringExpression()