class MyFifo():
      def __init__(self, content=[]):
          if isinstance(content, (tuple, list, str)):
              self.content = [i for i in content]
          else:
              self.content = []
  
      def __repr__(self):
          return str(self.content)
  
      def __add__(self, fifo):
          # return MyFifo(self.content[:] + fifo.content[:])
          return MyFifo(self.content + fifo.content)
  
      def put_in(self, item):
          self.content.append(item)
  
      def take_out(self):
          if len(self.content) > 0:
              return self.content.pop(0)
  
      def interactive(self):
          while True:
              k = input("> ")
              if k == "":
                  break
              if k != "?":
                  self.put_in(k)
                  print(self.__repr__())
              else:
                  out = self.take_out()
                  if out:
                      print(out)
                  else:
                      print('The Queue is empty.')
  
  
  # def main():
  print('Selftest for Class MyFifo:')
  f0 = MyFifo(1)
  print(f0)
  # f1 = MyFifo((1, 2, 3))
  # f1 = MyFifo('123')
  f1 = MyFifo([1, 2, 3])
  f2 = MyFifo((3, 4, 5))
  print(f1, f2)
  f3 = f1 + f2
  print(f3)
  print(f3.take_out())
  print(f1, f2, f3)
  f3.interactive()
  
  # if __name__ == '__main__':
  # main()