code: def ltrim(self, key, start, stop):
          
          return self._execute([b'LTRIM', key, start, stop], b'OK')
docs: Crop a list to the specified range.
  
          :param key: The list's key
          :type key: :class:`str`, :class:`bytes`
          :param int start: zero-based index to first element to retain
          :param int stop: zero-based index of the last element to retain
          :returns: did the operation succeed?
          :rtype: bool
          :raises: :exc:`~tredis.exceptions.TRedisException`
  
          Trim an existing list so that it will contain only the specified
          range of elements specified.
  
          Both `start` and `stop` are zero-based indexes, where 0 is the first
          element of the list (the head), 1 the next element and so on.
          For example: ``ltrim('foobar', 0, 2)`` will modify the list stored at
          ``foobar`` so that only the first three elements of the list will
          remain.
  
          `start` and `stop` can also be negative numbers indicating offsets
          from the end of the list, where -1 is the last element of the list,
          -2 the penultimate element and so on.
  
          Out of range indexes will not produce an error: if `start` is larger
          than the `end` of the list, or `start > end`, the result will be an
          empty list (which causes `key` to be removed). If `end` is larger
          than the end of the list, Redis will treat it like the last element
          of the list.
  
          A common use of LTRIM is together with LPUSH / RPUSH. For example::
  
              client.lpush('mylist', 'somelement')
              client.ltrim('mylist', 0, 99)
  
          This pair of commands will push a new element on the list, while
          making sure that the list will not grow larger than 100 elements.
          This is very useful when using Redis to store logs for example. It is
          important to note that when used in this way LTRIM is an O(1)
          operation because in the average case just one element is removed
          from the tail of the list.
  
          .. note::
  
             Time complexity: ``O(N)`` where `N` is the number of elements to
             be removed by the operation.