Clean up unnecessary exception imports

ref-test/app/__init__.py

@@ -7,7 +7,6 @@ from flask import flash, Flask, render_template, request
 from flask.helpers import abort, url_for
 from flask.json import jsonify
 from flask_wtf.csrf import CSRFError
-from sqlalchemy.exc import SQLAlchemyError
 from werkzeug.middleware.proxy_fix import ProxyFix
 
 from datetime import datetime