How work with Java StringTemplate boolean?
===

I wrote the following StringTemplate template lines:
    
    <instance.attributes: { attr | <attr.value>}>
    <instance.attributes: { attr | <if(attr.value)>skip<else>don't skip<endif> } >

in order to write skip if the Object value return by `Instance.getAttributes().getValue()` is a boolean which value is true.

This result in

    1
    skip

and

    0
    skip

(for now I only have one attribute)

What is the problem and why I don't get ?

    0
    don't skip