code: def pretty_print(self, carrot=False):
          
          lineno = self.lineno
          padding = 0
          if lineno < 1000:
              padding = 1
          if lineno < 100:
              padding = 2
          if lineno < 10:
              padding = 3
  
          string = str(lineno) + (' ' * padding) + '|' + self.string
          if carrot:
              string += '\n' + (' ' * (self.col + 5))
          return string
docs: Return a string of this line including linenumber.
          If carrot is True then a line is added under the string with a carrot
          under the current character position.