@Nullable
  public static List<String> strListValue(PyAstExpression value) {
    while (value instanceof PyAstParenthesizedExpression) {
      value = ((PyAstParenthesizedExpression)value).getContainedExpression();
    }
    if (value instanceof PyAstSequenceExpression) {
      final PyAstExpression[] elements = ((PyAstSequenceExpression)value).getElements();
      List<String> result = new ArrayList<>(elements.length);
      for (PyAstExpression element : elements) {
        if (!(element instanceof PyAstStringLiteralExpression)) {
          return null;
        }
        result.add(((PyAstStringLiteralExpression)element).getStringValue());
      }
      return result;
    }
    return null;
  }
@Nullable
  public static List<String> strListValue(PyAstExpression value)