zvikico

import itertools

def iter_interleave(*args):
    iterators = [(x for x in it) for it in args]
    has_values = [True for _ in xrange(len(iterators))]
    while max(has_values):
        for it, has_value, i in itertools.izip(iterators, has_values, xrange(len(iterators))):
            if has_value:
                try:
                    value = it.next()

zvikico

class ReducingDict(dict):

    def __init__(self, function, initial = None):
        self._function = function
        self._initial = initial
        super(ReducingDict, self).__init__()

    def __setitem__(self, key, new_value):
        if key in self:

zvikico

import copy

class ReducingDict(dict):

    def __init__(self, function, initial = None):
        self._function = function
        self._initial = initial
        super(ReducingDict, self).__init__()

    def __setitem__(self, key, new_value):