Python caching function result

fifo_cache.py

from collections import OrderedDict

def fifo_cache(max_size=128):
    def decorator(func):
        cache = OrderedDict()

        def _wrapper(*args, **kwargs):
            key = (tuple(args), tuple(sorted(kwargs.items())))
            if key not in cache:
                if len(cache) == max_size:
                    cache.pop(cache.iterkeys().next())
                value = func(*args, **kwargs)
                cache[key] = value
            return cache[key]

        return _wrapper

    return decorator