pylint issues resolved

Ran tests, and black afterwards. Updated changes.rst and included pre-commit hooks as required.  Ran isort on imports.

examples/tutorial/tests/conftest.py

@@ -2,10 +2,8 @@ import os
 import tempfile
 
 import pytest
-
 from flaskr import create_app
-from flaskr.db import get_db
-from flaskr.db import init_db
+from flaskr.db import get_db, init_db
 
 # read in SQL for populating test data
 with open(os.path.join(os.path.dirname(__file__), "data.sql"), "rb") as f: