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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def deprecated(fn):
 """Mark a function as deprecated and warn the user on use."""

    @functools.wraps(fn)
    def wrapper(*args, **kwargs):
        warnings.warn(fn.__doc__.split('\n')[0],
                      category=DeprecationWarning, stacklevel=2)
        return fn(*args, **kwargs)
    return wrapper