code: def parse_parameters(self):
          
          self.parse_region()
          self.parse_size()
          self.parse_rotation()
          self.parse_quality()
          self.parse_format()
docs: Parse the parameters of an Image Information request.
  
          Will throw an IIIFRequestError on failure, set attributes on
          success. Care is taken not to change any of the artibutes
          which store path components. All parsed values are stored
          in new attributes.