Started from scratch and failed

Issue with register_blueprint

ref-test/test/subfolder/__init__.py

@@ -0,0 +1,8 @@
+from flask import Flask
+from .deeper import t
+
+def create_app():
+    app = Flask(__name__)
+    app.register_blueprint(t)
+
+    return app

ref-test/test/subfolder/deeper/__init__.py

@@ -0,0 +1,5 @@
+from flask import Blueprint
+
+t = Blueprint(name='test', import_name=__name__)
+
+from . import foo

ref-test/test/subfolder/deeper/foo.py

@@ -0,0 +1,5 @@
+from . import t
+
+@t.route('/')
+def _t():
+    return 'Test'

ref-test/test/test.py

@@ -0,0 +1,5 @@
+from subfolder import create_app
+
+app = create_app()
+app.run()
+