<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def deprecated(message):
 """Deprecated function decorator."""

    def wrapper(fn):
        def deprecated_method(*args, **kargs):
            warnings.warn(message, DeprecationWarning, 2)
            return fn(*args, **kargs)
        # TODO: use decorator ?  functools.wrapper ?
        deprecated_method.__name__ = fn.__name__
        deprecated_method.__doc__ = "%s\n\n%s" % (message, fn.__doc__)
        return deprecated_method
    return wrapper