code: def cut(self, line):
          
          result = []
          line = self.line(line)
  
          for i, field in enumerate(self.positions):
              try:
                  index = _setup_index(field)
                  try:
                      result += line[index]
                  except IndexError:
                      result.append(self.invalid_pos)
              except ValueError:
                  result.append(str(field))
              except TypeError:
                  result.extend(self._cut_range(line, int(field[0]), i))
  
          return ''.join(result)
docs: Returns selected positions from cut input source in desired
          arrangement.
  
          Argument:
              line -      input to cut