def aggregate(iterable, func, selector=None, seed=_undefined):
func = Function(func, arity=2)
selector = Function(selector, arity=1)
if seed is _undefined:
return selector(compatible.reduce(func, iterable))
else:
return selector(compatible.reduce(func, iterable, seed))
def count(iterable, pred=None):
pred = Function(pred or utils.always(True), arity=1)
return compatible.reduce(lambda n, _: n + 1, where(iterable, pred), 0)
