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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 slice(cls, *args, **kwargs):
 """Take a slice of a DataSetFamily to produce a dataset indexed by asset and date. Parameters *args **kwargs The coordinates to fix along each extra dimension. Returns ------- dataset : DataSet A regular pipeline dataset indexed by asset and date. Notes ----- The extra dimensions coords used to produce the result are available under the ``extra_coords`` attribute. """

        coords, hash_key = cls._canonical_key(args, kwargs)
        try:
            return cls._slice_cache[hash_key]
        except KeyError:
            pass

        Slice = cls._make_dataset(coords)
        cls._slice_cache[hash_key] = Slice
        return Slice