anchor.diff:              ),
               gen_w1c()
           },
  -        Defaults ++ Mult ++ DatatypeOrConsistent ++ FastPath).
  +        Defaults ++ Mult ++ DatatypeOrConsistent ++ WriteOnce).
   
   gen_allow_mult() ->
       ?LET(Mult, frequency([{9, bool()}, {1, binary()}]), [{allow_mult, Mult}]).
  
positive.code: -spec validate_w1c_props(props(), props(), errors()) -> {props(), props(), errors()}.
  validate_w1c_props(Unvalidated, Valid, Errors) ->
      ensure_not_present(Unvalidated, Valid, Errors,
                         [{consistent, true, "Fast Path buckets must not be consistent=true"},
                          {datatype, "Fast Path buckets must not have datatype defined"}
                         ]).
  
  %% @private any property in `InvalidPropsSpec' present in
  
negative.code:     % write_once and consistent can't both be true
      case get_boolean(write_once, New) of
          true ->
              {lists:keydelete(consistent, 1, New), [], [{consistent, "Write once buckets must be not be consistent=true"}]};
          _ ->
              {lists:keydelete(consistent, 1, New), [{consistent, true}], []}
      end;
  