code: def _get_match(self, prefix):
          
          # (hard coded) If we match a CPR response, return Keys.CPRResponse.
          # (This one doesn't fit in the ANSI_SEQUENCES, because it contains
          # integer variables.)
          if _cpr_response_re.match(prefix):
              return Keys.CPRResponse
  
          elif _mouse_event_re.match(prefix):
              return Keys.Vt100MouseEvent
  
          # Otherwise, use the mappings.
          try:
              return ANSI_SEQUENCES[prefix]
          except KeyError:
              return None
docs: Return the key that maps to this prefix.