human
Complete this python program:
def decorate_fn_with_doc(new_fn, old_fn, additional_text=''):
assistant
#Here is the Python code you requested.

    """Make new_fn have old_fn\s doc string. This is particularly useful
    for the ``do_...`` commands that hook into the help system.
    Adapted from from a comp.lang.python posting
    by Duncan Booth.
    """
    def wrapper(*args, **kw):
        return new_fn(*args, **kw)
    if old_fn.__doc__:
        wrapper.__doc__ = (old_fn.__doc__ + additional_text)
    return wrapper