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

    def wrapper(func):
        if ((source.__doc__ is None) or (len(source.__doc__) == 0)):
            raise ValueError('Cannot    copy    docstring:    docstring    was    empty.')
        doc = source.__doc__
        if (func.__doc__ is not None):
            doc += func.__doc__
        func.__doc__ = doc
        return func
    return wrapper

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

def copy_doc(source):