human
Here's a good function header given the following:
I wrote the below code

    def _tidy(fn):
        fn._sa_instrumented = True
        fn.__doc__ = getattr(list, fn.__name__).__doc__
    def append(fn):
        def append(self, item, _sa_initiator=None):
            item = __set(self, item, _sa_initiator)
            fn(self, item)
        _tidy(append)
        return append
    def remove(fn):
        def remove(self, value, _sa_initiator=None):
            __before_delete(self, _sa_initiator)
            fn(self, value)
            __del(self, value, _sa_initiator)
        _tidy(remove)
        return remove
    def insert(fn):
        def insert(self, index, value):
            value = __set(self, value)
            fn(self, index, value)
        _tidy(insert)
        return insert
    def __setitem__(fn):
        def __setitem__(self, index, value):
            if (not isinstance(index, slice)):
                existing = self[index]
                if (existing is not None):
                    __del(self, existing)
                value = __set(self, value)
                fn(self, index, value)
            else:
                step = (index.step or 1)
                start = (index.start or 0)
                if (start < 0):
                    start += len(self)
                if (index.stop is not None):
                    stop = index.stop
                else:
                    stop = len(self)
                if (stop < 0):
                    stop += len(self)
                if (step == 1):
                    for i in range(start, stop, step):
                        if (len(self) > start):
                            del self[start]
                    for (i, item) in enumerate(value):
                        self.insert((i + start), item)
                else:
                    rng = list(range(start, stop, step))
                    if (len(value) != len(rng)):
                        raise ValueError(('attempt    to    assign    sequence    of    size    %s    to    extended    slice    of    size    %s' % (len(value), len(rng))))
                    for...

What's a good function header?
assistant
#Here's a good function header.

def _list_decorators():