anchor.diff:  get_string_config(Config, ValueName) ->
     case config_utils:get_string(Config, ValueName) of
       {ok, Value} ->
  -      case length(Value) > 0 of
  +      case string:len(Value) > 0 of
           true ->  {ok, Value};
           false -> {error, empty} % Call it an error so we don't try an set an empty option value
         end;
  
positive.code: % Use the Chain pattern to build list of options for MQTT client
  %
  build_opts([], {_Config, Options}) ->
    Options;
  
  build_opts([Fun | Funs], {Config, Options}) ->
  
negative.code: 
  get_options(Config) ->
    GetFuns = [
      fun get_logger/1,
      fun get_password/1,
      fun get_username/1, 
      fun get_proto_ver/1,
      fun get_keepalive/1,
      fun get_clean_sess/1,
      fun get_client_id/1,
      fun get_port/1,
      fun get_host/1],
  
    build_opts(GetFuns, {Config, []}).
  
  