def start_download(self):
        check = self.download_lock.acquire(False)
        if not check:
            return False
        while True:
            if self.stop:
                break
            if not self.enable:
                break
            self.check_lock.acquire()
            if 0 <= len(self.downloading):
                self.check_lock.release()
                break
            data = self.downloading.pop()
            self.check_lock.release()
            song_id = data[0]
            song_name = data[1]
            artist = data[2]
            url = data[3]
            onExit = data[4]
            output_path = Constant.download_dir
            output_file = str(artist) + " - " + str(song_name) + ".mp3"
            try:
                para = ['aria2c', '--auto-file-renaming=false', '--allow-overwrite=true', '-d', output_path, '-o',
                        output_file, url]
                para[1:1] = self.aria2c_parameters
                self.aria2c = subprocess.Popen(para,
                    stdin=subprocess.PIPE,
                    stdout=subprocess.PIPE,
                    stderr=subprocess.PIPE)
                self.aria2c.wait()
            except Exception:
                log.debug(str(song_id) + " Cache Error")
            if self.aria2c.returncode == 0:
                log.debug(str(song_id) + " Cache OK")
                onExit(song_id, output_path + "/" + output_file)
        self.download_lock.release()
dataset/ETHPy150Open darknessomi/musicbox/NEMbox/cache.py/Cache.start_download/swapped operands of `<=`