human
I wrote the below code

    name = (name or 'mask')
    def numbered_names():
        i = 0
        while True:
            (yield (name + str(i)))
            i += 1
    names = numbered_names()
    def Dummy(*args, **kwargs):
        from sympy import Dummy
        return Dummy(next(names), *args, **kwargs)
    expr = eq
    if expr.is_commutative:
        return (eq, {}, [])
    rep = []
    nc_obj = set()
    nc_syms = set()
    pot = preorder_traversal(expr, keys=default_sort_key)
    for (i, a) in enumerate(pot):
        if any(((a == r[0]) for r in rep)):
            pot.skip()
        elif (not a.is_commutative):
            if a.is_Symbol:
                nc_syms.add(a)
            elif (not (a.is_Add or a.is_Mul or a.is_Pow)):
                if all((s.is_commutative for s in a.free_symbols)):
                    rep.append((a, Dummy()))
                else:
                    nc_obj.add(a)
                pot.skip()
    if ((len(nc_obj) == 1) and (not nc_syms)):
        rep.append((nc_obj.pop(), Dummy()))
    elif ((len(nc_syms) == 1) and (not nc_obj)):
        rep.append((nc_syms.pop(), Dummy()))
    nc_obj = sorted(nc_obj, key=default_sort_key)
    for n in nc_obj:
        nc = Dummy(commutative=False)
        rep.append((n, nc))
        nc_syms.add(nc)
    expr = expr.subs(rep)
    nc_syms = list(nc_syms)
    nc_syms.sort(key=default_sort_key)
    return (expr, ({v: k for (k, v) in rep} or None), nc_syms)

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

def _mask_nc(eq, name=None):