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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 get_canonical_key_id(self, key_id):
 """ get_canonical_key_id is used by get_canonical_key, see the comment for that method for more explanation. Keyword arguments: key_id -- the key id (e.g. '12345') returns the canonical key id (e.g. '12') """

        shard_num = self.get_shard_num_by_key_id(key_id)
        return self._canonical_keys[shard_num]