new_contents: 
  def krange(begin, end):
      value = begin
      while value < end:
          yield value
          value += 1
      return
  
  
  def main():
      for i in krange(0, 10):
          print(i)
  
  
  if __name__ == '__main__':
      main()
  
subject: Add krange for helping understanding concept of generator in python