reduce implemented recursively and iteratively

reduce.py

def reduce(function, sequence, initial=None):
    i = iter(sequence)
    try:
        initial = initial if initial is not None else next(i)
    except StopIteration:
        raise TypeError("reduce() of empty sequence with no initial value")
    try:
        return reduce(function, i, function(initial, next(i)))
    except StopIteration:
        return initial


def reduce(function, sequence, initial=None):
    i = iter(sequence)
    try:
        result = initial if initial is not None else next(i)
    except StopIteration:
        raise TypeError("reduce() of empty sequence with no initial value")
    for x in i:
        result = function(result, x)
    return result