如何利用Python对接又拍云接口，实现视频裁剪与合并功能

import requestsimport hashlibimport time# 替换为你的API密钥和存储空间名operator = 'your_operator'password = 'your_password'bucket = 'your_bucket_name'# 获取当前时间戳timestamp = int(time.time())# 构造签名字符串sign_string = '{0}&{1}&{2}'.format(operator, password, timestamp)# 计算签名md5 = hashlib.md5()md5.update(sign_string.encode('utf-8'))signature = md5.hexdigest()# 发起视频裁剪任务def crop_video(filename, start, end):    # 请求URL    url = 'http://v0.api.upyun.com/{0}/transcoding/'.format(bucket)    # 构造请求参数    params = {        'source': filename,        'start': start,        'end': end,        'notify_url': 'http://your_notify_url',        'signature': signature,        'timestamp': timestamp    }    # 发起POST请求    response = requests.post(url, data=params)    # 获取响应结果    result = response.json()    return result# 发起视频合并任务def merge_videos(filenames, save_as):    # 请求URL    url = 'http://v0.api.upyun.com/{0}/merge/'.format(bucket)    # 构造请求参数    params = {        'files': ';'.join(filenames),        'save_as': save_as,        'signature': signature,        'timestamp': timestamp    }    # 发起POST请求    response = requests.post(url, data=params)    # 获取响应结果    result = response.json()    return result# 调用视频裁剪接口示例crop_result = crop_video('origin_video.mp4', 10, 20)print(crop_result)# 调用视频合并接口示例merge_result = merge_videos(['video1.mp4', 'video2.mp4', 'video3.mp4'], 'merged_video.mp4')print(merge_result)