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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 ltrim(self, key, start, stop):
 """Emulate ltrim."""

        redis_list = self._get_list(key, 'LTRIM')
        if redis_list:
            start, stop = self._translate_range(len(redis_list), start, stop)
            self.redis[self._encode(key)] = redis_list[start:stop + 1]
        return True