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

    def conglomerate(expr):
        '    Conglomerate    together    identical    args    x    +    x    ->    2x    '
        groups = sift(expr.args, key)
        counts = dict(((k, sum(map(count, args))) for (k, args) in groups.items()))
        newargs = [combine(cnt, mat) for (mat, cnt) in counts.items()]
        if (set(newargs) != set(expr.args)):
            return new(type(expr), *newargs)
        else:
            return expr
    return conglomerate

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

def glom(key, count, combine):