Setup the pool parameters like number of workers and output queue size

def setup(self, workers=1, qsize=0):
        """Setup the pool parameters like number of workers and output queue size"""
        if workers <= 0:
            raise ValueError("workers have to be greater then zero")
        if qsize < 0:
            raise ValueError("qsize have to be greater or equal zero")
        self.qsize = qsize # output que size
        self.workers = workers
        return self