more flake8. lots of unused imports and variables that didn't get used. i tried to preserve old variable names as comments when it looked like they were useful (eg when they were describing timestamps)

tests/app/organisation/test_rest.py

@@ -1,10 +1,7 @@
-from flask import json
 import pytest
 
 from app.models import Organisation
 
-from tests import create_authorization_header
-
 
 def test_get_organisations(admin_request, notify_db, notify_db_session):
     org1 = Organisation(colour='#FFFFFF', logo='/path/image.png', name='Org1')
@@ -59,7 +56,7 @@ def test_post_create_organisation_without_logo_is_ok(admin_request, notify_db_se
         'name': 'test organisation',
         'colour': '#0000ff',
     }
-    response = admin_request.post(
+    admin_request.post(
         'organisation.create_organisation',
         _data=data,
         _expected_status=201,