Started from scratch and failed

Issue with register_blueprint

ref-test/app/__init__.py

@@ -0,0 +1,52 @@
+from .bootstrap import bootstrap
+from .config import DevelopmentConfig as Config
+from .csrf import csrf
+from .database import db
+from .login_manager import login_manager
+from .mail import mail
+
+from flask import Flask
+from flask_wtf.csrf import CSRFError
+from flask.json import jsonify
+from werkzeug.middleware.proxy_fix import ProxyFix
+
+from datetime import datetime
+
+from .admin.views import admin
+from .api.views import api
+from .common.views import common
+from .quiz.views import quiz
+
+def create_app():
+    
+    app = Flask(__name__)
+    app.config.from_object(Config())
+    app.wsgi_app = ProxyFix(app.wsgi_app, x_proto= 1, x_host= 1)
+
+    # bootstrap.init_app(app)
+    # csrf.init_app(app)
+    # db.init_app(app)
+    # login_manager.init_app(app)
+    # mail.init_app(app)
+
+    # login_manager.login_view = 'admin._login'
+    # @login_manager.user_loader
+    # def _load_user(user_id):
+    #     pass
+
+    # @app.errorhandler(404)
+    # def _404_handler(error):
+    #     return jsonify({'error':'404 — Not Found'}), 404
+    # @app.errorhandler(CSRFError)
+    # def _csrf_handler():
+    #     return jsonify({'error':'Could not validate a secure connection.'}), 403
+    # @app.context_processor
+    # def _now():
+    #     return {'now': datetime.utcnow()}
+
+    app.register_blueprint(admin, url_prefix='/admin')
+    app.register_blueprint(api, url_prefix='/api')
+    app.register_blueprint(common)
+    app.register_blueprint(quiz)
+
+    return app