class Transformers {

   static MessageBody inputToExecuteMessage(JsonElement payload) {
      List<GoogleCommand> commands = ImmutableList.of();
      if(payload != null) {
         ExecutePayload execute = GSON.fromJson(payload, ExecutePayload.class);
         if(execute.getCommands() != null) {
            ImmutableList.Builder<GoogleCommand> builder = ImmutableList.builder();
            execute.getCommands().forEach((c) -> addCommands(c, builder));
            commands = builder.build();
         }
      }
      return GoogleService.ExecuteRequest.builder()
            .withCommands(commands.stream().map(GoogleCommand::toMap).collect(Collectors.toList()))
            .build();
   }

   private  Transformers();

}