code: def lines(self) -> str:
          
          if self.definition is None:
              return ''
          source = ''
          lines = self.definition.source
          offset = self.definition.start  # type: ignore
          lines_stripped = list(reversed(list(dropwhile(is_blank,
                                                        reversed(lines)))))
          numbers_width = len(str(offset + len(lines_stripped)))
          line_format = '{{:{}}}:{{}}'.format(numbers_width)
          for n, line in enumerate(lines_stripped):
              if line:
                  line = ' ' + line
              source += line_format.format(n + offset, line)
              if n > 5:
                  source += '        ...\n'
                  break
          return source
docs: Return the source code lines for this error.