<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def processes(self, processes):
        '''Set the number of concurrent processes the ABC will utilize for
        fitness function evaluation; if <= 1, single process is used

        Args:
            processes (int): number of concurrent processes
        '''

        if self._processes > 1:
            self._pool.close()
            self._pool.join()
            self._pool = multiprocessing.Pool(processes)
        else:
            self._pool = None
        self._logger.log('debug', 'Number of processes set to {}'.format(
            processes
        ))