How to use Gargl and pygargl to download file from website

Hi,

I am trying to use Gargl and pygargl to download a xml file from website. After get into the website, I need to click some selections to confirm which items to be downloaded, then I click the button of "export data", it will download the xml file from the website to my computer. And there is some information "content-disposition:attachment; filename=Export090916.xml" from the response headers.But I cannot find anything in response body. Could you please give me some ideas about how to download the xml file using Gargl and pygargl?

Thanks!