Selenium opening pdf in new window

[test]

Here i found the following code:

page_src = br.page_source.encode("utf-8") // support unicode characters
f = open('page.html', 'w')
f.write(page_src)

but the encoding seems to be different from that needed for a pdf file. I'm getting a 'file type not supported' error on trying to see the downloaded file.
I think i'm doing something wrong...downloading a file shouldn't be so difficult..
Any help, welcome