code: def restore(self):
          
          # If there are no backup keys, do nothing...
          if len(list(self.backup.keys())) == 0:
              return
          for key in self.backup.keys():
              if key != 'WCSCDATE':
                  self.__dict__[self.wcstrans[key]] = self.orig_wcs[self.backup[key]]
  
          self.update()
docs: Reset the active WCS keywords to values stored in the
              backup keywords.