code: def sadd(self, key, *members):
          
          return self._execute([b'SADD', key] + list(members), len(members))
docs: Add the specified members to the set stored at key. Specified
          members that are already a member of this set are ignored. If key does
          not exist, a new set is created before adding the specified members.
  
          An error is returned when the value stored at key is not a set.
  
          Returns :data:`True` if all requested members are added. If more
          than one member is passed in and not all members are added, the
          number of added members is returned.
  
          .. note::
  
             **Time complexity**: ``O(N)`` where ``N`` is the number of members
             to be added.
  
          :param key: The key of the set
          :type key: :class:`str`, :class:`bytes`
          :param members: One or more positional arguments to add to the set
          :type key: :class:`str`, :class:`bytes`
          :returns: Number of items added to the set
          :rtype: bool, int