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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 tap(f):
 """ "Tap" a Deferred callback chain with a function whose return value is ignored. """

    @wraps(f)
    def _cb(res, *a, **kw):
        d = maybeDeferred(f, res, *a, **kw)
        d.addCallback(lambda ignored: res)
        return d
    return _cb