Python 下载超大文件

def download_file(url, file_pname, chunk_size=1024*4):
    """
    url: file url
    file_pname: file save path
    chunk_size: chunk size
    """
    # 第一种
    response_data_file = requests.get(url, stream=True)
    with open(file_pname, ‘wb‘) as f:
        for chunk in response_data_file.iter_content(chunk_size=chunk_size):
            if chunk:
                f.write(chunk)

    # 第二种
    with requests.get(url, stream=True) as req:
        with open(file_pname, ‘wb‘) as f:
            for chunk in req.iter_content(chunk_size=chunk_size):
                if chunk:
                    f.write(chunk)