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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 sadd(self, key, *values):
 """Emulate sadd."""

        if len(values) == 0:
            raise ResponseError("wrong number of arguments for 'sadd' command")
        redis_set = self._get_set(key, 'SADD', create=True)
        before_count = len(redis_set)
        redis_set.update(map(self._encode, values))
        after_count = len(redis_set)
        return after_count - before_count