UnboundLocalError: local variable 'response' referenced before assignment

[peterbe]

Describe the bug
If something goes wrong in self._session.request() the variable response will never be set. Leading to a
UnboundLocalError: local variable 'response' referenced before assignment

Your code
Sorry.
Error from my Rollbar:

Expected behavior
Requests fail and that's fine. Judging from skimming the code, it's trying to package a message to go with raising a SpotifyException but it's failing to do so.

Output
Paste and format errors (with complete stacktrace) or logs. Make sure to remove sensitive information.

Environment:

• spotipy version: spotipy==2.13.0

Additional context
Relying on UnboundLocalError from a caller isn't nice. If it was SpotifyException I could do something like this:

from spotipy.exceptions import SpotifyException

try:
    something_that_calls_spotipy(...)
except SpotifyException as err:
    logger.warning("Oh no. Spotify exception...")

[stephanebruckert]

Should be fixed by #580