Things you didn't know about Python(speakerdeck.com)

    class cached_property(object):

        def __init__(self, fget):
            self.fget = fget
            self.__name__ = fget.__name__
            self.__module__ = fget.__module__
            self.__doc__ = fget.__doc__

        def __get__(self, obj, objtype=None):
            if obj is None:
                return self
            value = self.fget(obj)
            # For a non-data descriptor (`__set__` is not defined),
            # `__dict__` takes precedence.
            obj.__dict__[self.__name__] = value
            return value