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

    if (replace_names is not None):
        replace_names = set(replace_names)
    def param(func):
        new_sig = None
        python_has_signature = python_has_wrapped = six.PY3
        if ((not python_has_signature) and (u'IPython' in sys.modules)):
            try:
                import IPython.utils.signatures
                signature = IPython.utils.signatures.signature
                Parameter = IPython.utils.signatures.Parameter
            except ImportError:
                pass
            else:
                python_has_signature = True
        elif python_has_signature:
            signature = inspect.signature
            Parameter = inspect.Parameter
        if (not python_has_signature):
            arg_spec = inspect.getargspec(func)
            _arg_names = arg_spec.args
            _has_varargs = (arg_spec.varargs is not None)
            _has_varkwargs = (arg_spec.keywords is not None)
        else:
            sig = signature(func)
            _has_varargs = False
            _has_varkwargs = False
            _arg_names = []
            params = list(sig.parameters.values())
            for p in params:
                if (p.kind is Parameter.VAR_POSITIONAL):
                    _has_varargs = True
                elif (p.kind is Parameter.VAR_KEYWORD):
                    _has_varkwargs = True
                else:
                    _arg_names.append(p.name)
            data_param = Parameter(u'data', Parameter.KEYWORD_ONLY, default=None)
            if _has_varkwargs:
                params.insert((-1), data_param)
            else:
                params.append(data_param)
            new_sig = sig.replace(parameters=params)
        arg_names_at_runtime = False
        if (not _has_varargs):
            arg_names = _arg_names[1:]
        elif (replace_names is None):
            arg_names = None
        elif (len(replace_names) == 0):
            arg_names = []
        elif ((len(_arg_names) > 1) and (positional_parameter_names is None)):
            if (len((replace_names -...

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

def _preprocess_data(replace_names=None, replace_all_args=False, label_namer=None, positional_parameter_names=None):