docs: def _getDone(self, done, undone):
          """Parses the done|undone state.
  
          :done: Done marking pattern.
          :undone: Not done marking pattern.
          :returns: Pattern for done|undone or None if neither were specified.
  
          """
          if done:
              return self._getPattern(done, True)
          if undone:
              return self._getPattern(undone, False)