code: def diff_missed_lines(self, filename):
          
          line_changed = []
          for line in self.file_source(filename):
              if line.status is not None:
                  is_new = not line.status
                  line_changed.append((line.number, is_new))
          return line_changed
docs: Return a list of 2-element tuples `(lineno, is_new)` for the given
          file `filename` where `lineno` is a missed line number and `is_new`
          indicates whether the missed line was introduced (True) or removed
          (False).