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

    os.chdir(str(tmpdir))
    wf = pe.Workflow(name=u'test_workflow')
    def _gen_tuple(size):
        return ([1] * size)
    def _sum_and_sub_mul(a, b, c):
        return (((a + b) * c), ((a - b) * c))
    def _inc(x):
        return (x + 1)
    params = pe.Node(utility.IdentityInterface(fields=[u'size', u'num']), name=u'params')
    params.inputs.num = 42
    params.inputs.size = 1
    gen_tuple = pe.Node(utility.Function(input_names=[u'size'], output_names=[u'tuple'], function=_gen_tuple), name=u'gen_tuple')
    ssm = pe.Node(utility.Function(input_names=[u'a', u'b', u'c'], output_names=[u'sum', u'sub'], function=_sum_and_sub_mul), name=u'sum_and_sub_mul')
    split = pe.Node(utility.Split(splits=[1, 1], squeeze=True), name=u'split')
    wf.connect([(params, gen_tuple, [((u'size', _inc), u'size')]), (params, ssm, [((u'num', _inc), u'c')]), (gen_tuple, split, [(u'tuple', u'inlist')]), (split, ssm, [((u'out1', _inc), u'a'), (u'out2', u'b')])])
    wf.run()

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

def test_aux_connect_function(tmpdir):