<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def logpath(self):
 """ Return the logfile path and filename as a string. The file with name self.logpath() is written to on flush(). The filename contains the log's timestamp and the names of players in the game. The logpath changes when reset() or _set_players() are called, as they change the timestamp and the players, respectively. """

        name = '{}-{}.catan'.format(self.timestamp_str(),
                                    '-'.join([p.name for p in self._players]))
        path = os.path.join(self._log_dir, name)
        if not os.path.exists(self._log_dir):
            os.mkdir(self._log_dir)
        return path