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

    if isinstance(_type, (tuple, list)):
        _type = tuple(_type)
        from pandas.io.formats.printing import pprint_thing
        type_repr = '|'.join(map(pprint_thing, _type))
    else:
        type_repr = ("'%s'" % _type)
    def inner(x):
        if (not isinstance(x, _type)):
            raise ValueError(('Value    must    be    an    instance    of    %s' % type_repr))
    return inner

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

def is_instance_factory(_type):