anchor.diff:      find_free_port([0]);
   find_free_port(Port) ->
       find_free_port([Port]).
  +
  +
  +-spec format(string(), list()) -> string().
  +format(FormatString, Items) ->
  +    lists:flatten(io_lib:format(FormatString, Items)).
  +
  +-spec exec(string()) -> pid().
  +exec(Cmd) ->
  +    _ = spawn(os, cmd, [Cmd]).
  
positive.code: get_number_of_vms() ->
      length(get_vms()).
  
  -spec add_vms(integer()) -> ok.
  add_vms(N) ->
      BaseScalarisPort = config:read(port),
      BaseYawsPort = config:read(yaws_port),
  
negative.code: init() ->
      case config:read(cloud_local_min_vms) of
          failed ->
              config:write(cloud_local_min_vms, 0),
              config:write(cloud_local_max_vms, ?PLUS_INFINITY);
          X -> X
      end,
  