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

    def f(rv):
        if (not (rv.is_Add or rv.is_Mul)):
            return rv
        def gooda(a):
            return ((a is not S.NegativeOne) and (a.is_real or (force and (a.is_real is not False))))
        def goodlog(l):
            a = l.args[0]
            return (a.is_positive or (force and (a.is_nonpositive is not False)))
        other = []
        logs = []
        log1 = defaultdict(list)
        for a in Add.make_args(rv):
            if ((a.func is log) and goodlog(a)):
                log1[()].append(([], a))
            elif (not a.is_Mul):
                other.append(a)
            else:
                ot = []
                co = []
                lo = []
                for ai in a.args:
                    if (ai.is_Rational and (ai < 0)):
                        ot.append(S.NegativeOne)
                        co.append((- ai))
                    elif ((ai.func is log) and goodlog(ai)):
                        lo.append(ai)
                    elif gooda(ai):
                        co.append(ai)
                    else:
                        ot.append(ai)
                if (len(lo) > 1):
                    logs.append((ot, co, lo))
                elif lo:
                    log1[tuple(ot)].append((co, lo[0]))
                else:
                    other.append(a)
        if ((not logs) and all((((len(log1[k]) == 1) and (log1[k][0] == [])) for k in log1))):
            return rv
        for (o, e, l) in logs:
            l = list(ordered(l))
            e = log((l.pop(0).args[0] ** Mul(*e)))
            while l:
                li = l.pop(0)
                e = log((li.args[0] ** e))
            (c, l) = (Mul(*o), e)
            if (l.func is log):
                log1[(c,)].append(([], l))
            else:
                other.append((c * l))
        for k in list(log1.keys()):
            log1[Mul(*k)] = log(logcombine(Mul(*[(l.args[0] ** Mul(*c)) for (c, l) in log1.pop(k)]), force=force))
        for k in ordered(list(log1.keys())):
            if (not (k in log1)):
 ...

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

def logcombine(expr, force=False):