public override IEquation VisitLessThanOrEqual(BasicParser.LessThanOrEqualContext context)
        {
            var expressionVisitor = new ExpressionVisitor();
            var left     = expressionVisitor.Visit(context.expression(0));
            var right    = expressionVisitor.Visit(context.expression(1));
            var equation = new LessThanOrEqualEquation(left, right);

            return(equation);
        }