@NotNull
  private static GrExpression stripParenthesis(GrExpression operand) {
    while (operand instanceof GrParenthesizedExpression) {
      GrExpression innerExpression = ((GrParenthesizedExpression)operand).getOperand();
      if (innerExpression == null) {
        break;
      }
      operand = innerExpression;
    }
    return operand;
  }
@NotNull
  private static GrExpression stripParenthesis(GrExpression operand)