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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 add_fast(self, filepath, hashfn=None, force=False):
 """ Bespoke function to add filepaths but set shortcircuit to True, which means only the first calculable hash will be stored. In this way only one "fast" hashing function need be called for each filepath. """

        if hashfn is None:
            hashfn = fast_hashes
        self.add(filepath, hashfn, force, shortcircuit=True)