code: def _get_tab(cls):
          
  
          if not cls._tabs['dec_cobs']:
              # Compute the COBS table for decoding
              cls._tabs['dec_cobs']['\xff'] = (255, '')
              cls._tabs['dec_cobs'].update(dict((chr(l), (l, '\0'))
                                                for l in range(1, 255)))
  
              # Compute the COBS table for encoding
              cls._tabs['enc_cobs'] = [(255, '\xff'),
                                       dict((l, chr(l))
                                            for l in range(1, 255)),
                                       ]
  
          return cls._tabs['dec_cobs'], cls._tabs['enc_cobs']
docs: Generate and return the COBS table.