code: def lpushx(self, key, *values):
          
          return self._execute([b'LPUSHX', key] + list(values))
docs: Insert values at the head of an existing list.
  
          :param key: The list's key
          :type key: :class:`str`, :class:`bytes`
          :param values: One or more positional arguments to insert at the
              beginning of the list.  Each value is inserted at the beginning
              of the list individually (see discussion below).
          :returns: the length of the list after push operations, zero if
              `key` does not refer to a list
          :rtype: int
          :raises: :exc:`~tredis.exceptions.TRedisException`
  
          This method inserts `values` at the head of the list stored at `key`,
          only if `key` already exists and holds a list. In contrary to
          :meth:`.lpush`, no operation will be performed when key does not yet
          exist.
  
          .. note::
  
             **Time complexity**: ``O(1)``