@Override
    public List<ExpressionNode> children() {
        return arguments;
    }
Creates a new condition node.

@param condition the condition of this
@param trueExpression  the expression to evaluate if the comparison is true
@param falseExpression the expression to evaluate if the comparison is false
@param trueProbability the probability that the condition will evaluate to true, or null if not known.
@throws IllegalArgumentException if trueProbability is non-null and not between 0.0 and 1.0
searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/rule/IfNode.java