anchor.diff:  
   -spec localhost([] | [url]) -> string().
   localhost(Options) ->
  -    case misc:is_ipv6() of
  +    case is_ipv6() of
           true ->
               case Options of
                   [] ->
  
positive.code: 
  -spec get_net_family() -> inet:address_family().
  get_net_family() ->
      case misc:is_ipv6() of
          true ->
              inet6;
          false ->
  
negative.code: 
  -spec get_proto_dist_type() -> string().
  get_proto_dist_type() ->
      case is_ipv6() of
          true ->
              "inet6_tcp";
          false ->
  