code: def lookup_string(self, keysym):
          
          s = self.keysym_translations.get(keysym)
          if s is not None:
              return s
  
          import Xlib.XK
          return Xlib.XK.keysym_to_string(keysym)
docs: Return a string corresponding to KEYSYM, or None if no
          reasonable translation is found.