Multi-key Groovy list sort with null handling

def records = [
    [name: 'ada', score: 90, age: 36],
    [name: 'bob', score: null, age: 41],
    [name: 'cy', score: 90, age: 28]
]
Comparator cmp = { a, b ->
    def left = a.score == null ? -1 : a.score
    def right = b.score == null ? -1 : b.score
    int byScore = right <=> left
    if (byScore != 0) return byScore
    int byAge = (a.age == null ? Integer.MAX_VALUE : a.age) <=> (b.age == null ? Integer.MAX_VALUE : b.age)
    byAge != 0 ? byAge : a.name <=> b.name
} as Comparator
def sorted = records.sort(false, cmp)
println sorted.collect { "${it.name}:${it.score}" }