func (iter Enumerator) Count(p Predicate) int {
	tally := 0
	for entry := range iter {
		if p(entry) {
			tally++
		}
	}
	return tally
}
func (iter Enumerator) Count(p Predicate) int {
	tally := 0
	for entry := range iter {
		if p(entry) {
			tally++
		}
	}
	return tally
}
// Count iterates over a list and keeps a running tally of the number of elements
// satisfy a predicate.