implementing functools.partial that prepends additional arguments

The documentation for functools.partial says that it is "roughly equivalent to":

def partial(func, *args, **keywords):
    def newfunc(*fargs, **fkeywords):
        newkeywords = keywords.copy()
        newkeywords.update(fkeywords)
        return func(*(args + fargs), **newkeywords)  # line to change
    newfunc.func = func
    newfunc.args = args
    newfunc.keywords = keywords
    return newfunc

If I wanted to implement a version that prepends the additional arguments, it seems like I'd just have to change the indicated line.

Are there any other features/gotchas that I should be worried about in just copying this code?