code: def comment(data, what):
      
      data = data.splitlines()
  
      data = map(
          lambda x: "#" + x if x.strip().split() == what.split() else x,
          data
      )
  
      return "\n".join(data)
docs: Comments line containing `what` in string `data`.
  
      Args:
          data (str): Configuration file in string.
          what (str): Line which will be commented out.
  
      Returns:
          str: Configuration file with commented `what`.