code: def _read_stdin():
      
      line = sys.stdin.readline()
      while line:
          yield line
          line = sys.stdin.readline()
docs: Generator for reading from standard input in nonblocking mode.
  
      Other ways of reading from ``stdin`` in python waits, until the buffer is
      big enough, or until EOF character is sent.
  
      This functions yields immediately after each line.