Improvement: Split download_attachment into 2 functions

[herronelou]

Hi.

We often need to download SG thumbnails from the thumbnail's URL.

We wrote code to do that which is essentially duplicated code from sg.download_attachment, the main difference being that instead of passing in an attachment, we directly pass the URL that the function extracts at

python-api/shotgun_api3/shotgun.py

Line 2936 in a1de54e

url = self.get_attachment_download_url(attachment)

Could we split the code into 2 functions, one to download by URL, and one to download by attachment, as it's essentially the same code?

I can put an MR if you're not against the idea.

[herronelou]

Also #343 had broken our own copy the the code, which is what prompted this idea so we don't need to maintain a separate branch..

[julien-lang]

Hello @herronelou, I'm sorry my #343 PR broke your code. I don't remember the details about it, but I did not think this method was used externally.

Anyway, I think your suggestion is a good idea, and we would be happy to review your contribution in a PR.