Hmm, I don't understand why we can assume that ['errors'][-1]['message'] will exist? Certainly a 500 Internal Server Error won't have that, right?

Won't this just result in a KeyError that will confound and frustrate users? BEFORE, at least we got a HEY, you got a 404! or something from r.raise_for_status().

Can we test this out? How do I test a 500 Internal Server Error. And the whole point of me adding the message here is that the 404 or whatever was not elucidating for people: a message like A file with that filename already exists is more practical for a Plotly user

Can we just do something like:

if not r.ok:
    message = ''
    if isinstance(parsed_response, dict):
        errors = parsed_respnonse.get('errors')
        if errors and errors[-1].get('message'):
            message = errors[-1]['message']
    if message:
        raise exceptions.PlotlyError(message)
    else:
        # shucks, we're stuck with a generic error...
        r.raise_for_status()

When would parsed_response not be a dict?

504 gateway timeouts. An HTML response gets returned instead of JSON

Also if the network is down. e.g. try turning off your wifi and then making the request

Yeah, that worked last time I tried in here...

Should we check if the figure is malformed though?
I tried passing a figure by changing the label data to datas (obviously wrong) and the request went through with all but a title and no plot.

Nope, we can assume that if the request is OK, the content should be predictable. Our api is supposed to remain backwards-compatible and so this shouldn't be a problem.

Okay, I'm good with this