Attempt to fix plugin by adding args and refactor

invenio/plugin/custom_invenio_plugin/__init__.py

@@ -1,10 +1,15 @@
 from flask import Blueprint
 
+blueprint = Blueprint(
+    "custom_menu",
+    __name__,
+)
+
 
 def init_app(app):
     """Initialize application."""
-    app.register_blueprint(views.blueprint)
+    app.register_blueprint(blueprint)
-    return app
-
 
     from . import views
+
+    return app

invenio/plugin/custom_invenio_plugin/views.py

@@ -10,9 +10,8 @@ blueprint = Blueprint(
 @blueprint.before_app_first_request
 def init_menu():
     """Add custom items to main menu."""
-    main_menu = current_menu
+    current_menu.submenu("main").register(
-
+        "amdmodel",
-    main_menu.submenu("main").register(
         text="About AM-D-Model",
         external_url="https://am-d-model.eu",
         order=0,