"Given a nonempty stream of `Comparable` values, return the largest value in the stream." see (`interface Comparable`, `function min`, `function largest`) shared Absent|Value max<Value,Absent>(Iterable<Value,Absent> values) given Value satisfies Comparable<Value> given Absent satisfies Null { value first=values.first; if (exists first) { variable value max=first; for (val in values.rest) { if (val>max) { max=val; } } return max; } else { return first; } }