code: def do_quality(self, quality):
          
          if (self.api_version >= '2.0'):
              if (quality != "default"):
                  raise IIIFError(code=501, parameter="default",
                                  text="Null manipulator supports only quality=default.")
          else:  # versions 1.0 and 1.1
              if (quality != "native"):
                  raise IIIFError(code=501, parameter="native",
                                  text="Null manipulator supports only quality=native.")
docs: Null implementation of quality.