public static ExpressionOperator simplify(final ExpressionOperator item) {
        final ExpressionItem expressionItem = simplifyExpressionItem(item);
        if (expressionItem == null) {
            return null;
        }
        if (expressionItem instanceof ExpressionOperator) {
            return (ExpressionOperator) expressionItem;
        }
        return ExpressionOperator.builder()
                .op(Op.AND)
                .children(Collections.singletonList(expressionItem))
                .build();
    }
Simplify an expression to improve comprehension and make processing faster.

@param item The expression to simplify.
@return The simplified expression.
stroom-query/stroom-query-api/src/main/java/stroom/query/api/ExpressionUtil.java