code: def progress(iter, **kwargs):
      
      if isinstance(iter, int):
          iter = xrange(iter)
      if hasattr(iter, '__len__') or 'target' in kwargs:
          cls = Progress
      else:
          cls = ProgressBase
  
      return cls(iter, **kwargs)
docs: 프로그래스 bar
      for i in progress(10):
          print i
  
      for i in progress(iter):
          print i