code: def add(self, pkgs):
          
          queue_list = self.packages()
          pkgs = list(OrderedDict.fromkeys(pkgs))
          print("\nAdd packages in the queue:\n")
          with open(self.queue_list, "a") as queue:
              for pkg in pkgs:
                  find = sbo_search_pkg(pkg)
                  if pkg not in queue_list and find is not None:
                      print("{0}{1}{2}".format(self.meta.color["GREEN"], pkg,
                                               self.meta.color["ENDC"]))
                      queue.write(pkg + "\n")
                      self.quit = True
                  else:
                      print("{0}{1}{2}".format(self.meta.color["RED"], pkg,
                                               self.meta.color["ENDC"]))
                      self.quit = True
              queue.close()
          if self.quit:
              print("")
docs: Add packages in queue if not exist