code: def list_keys(self, pattern='*', db=0):
          
          lines = output_lines(self.exec_redis_cli('KEYS', [pattern], db=db))
          return [] if lines == [''] else lines
docs: Run the ``KEYS`` command and return the list of matching keys.
  
          :param pattern: the pattern to filter keys by (default ``*``)
          :param db: the db number to query (default ``0``)