@Override
    public boolean equals(Object o) {
        if (! (o instanceof FieldResultTransform)) return false;
        FieldResultTransform other = (FieldResultTransform)o;

        return
            this.fieldName.equals(other.fieldName) &&
            this.transform.equals(other.transform) &&
            this.argument.equals(other.argument);
    }
Returns the argument of this (used as input to the backend docsum rewriter)
config-model/src/main/java/com/yahoo/schema/derived/FieldResultTransform.java