Groovy Higher order functions

## Groovy-Higher-order-functions.groovy
class Person {
    String name
    int age
    Gender gender
    enum Gender {
        MALE, FEMALE, UNKNOWN
    }
}

def persons = [new Person(name: 'Bob',   age: 25, gender: Person.Gender.MALE),
               new Person(name: 'Alice', age: 42, gender: Person.Gender.FEMALE)]

persons.findAll {
    Person v ->
        (v.age < 27 &&
         v.age > 24 &&
        (v.gender == Person.Gender.MALE || v.gender ==Person.Gender.UNKNOWN))
}.collect{ "${it.name}, ${it.age}, ${it.gender}" }