Python functools 模块，html() 实例源码

def memoize(fn):
    """
    https://stackoverflow.com/questions/1988804/what-is-memoization-and-how-can-i-use-it-in-python
    unbounded memoize
    alternate in py3: https://docs.python.org/3/library/functools.html
    lru_cache
    """
    mem = {}

    def _fn(*args, **kwargs):
        kwargs_tuple = _dict_to_tuple(kwargs)
        if (args, kwargs_tuple) not in mem:
            mem[(args, kwargs_tuple)] = fn(*args, **kwargs)
        return mem[(args, kwargs_tuple)]
    return _fn