functools.py

def partial(func, *args, **kwargs):
    def _partial(*more_args, **more_kwargs):
        kw = kwargs.copy()
        kw.update(more_kwargs)
        return func(*(args + more_args), **kw)
    return _partial


def update_wrapper(wrapper, wrapped, assigned=None, updated=None):
    # Dummy impl
    return wrapper


def wraps(wrapped, assigned=None, updated=None):
    # Dummy impl
    return lambda x: x


def reduce(function, iterable, initializer=None):
    it = iter(iterable)
    if initializer is None:
        value = next(it)
    else:
        value = initializer
    for element in it:
        value = function(value, element)
    return value


# CPython git v3.4.10
def cmp_to_key(mycmp):
    """Convert a cmp= function into a key= function"""
    class K(object):
        __slots__ = ['obj']
        def __init__(self, obj):
            self.obj = obj
        def __lt__(self, other):
            return mycmp(self.obj, other.obj) < 0
        def __gt__(self, other):
            return mycmp(self.obj, other.obj) > 0
        def __eq__(self, other):
            return mycmp(self.obj, other.obj) == 0
        def __le__(self, other):
            return mycmp(self.obj, other.obj) <= 0
        def __ge__(self, other):
            return mycmp(self.obj, other.obj) >= 0
        def __ne__(self, other):
            return mycmp(self.obj, other.obj) != 0
        __hash__ = None
    return K