@gen.coroutine
    def set_numprocesses(self, np):
        if np < 0:
            np = 0
        if self.singleton and np > 1:
            raise ValueError('Singleton watcher has a single process')
        self.numprocesses = np
        yield self.manage_processes()
        raise gen.Return(self.numprocesses)
dataset/ETHPy150Open circus-tent/circus/circus/watcher.py/Watcher.set_numprocesses/original