Error to start project could not import todo.todo

I was creating my flask project but I get this error

(venv) C:\routeproject>python -m flask run
 * Serving Flask app 'todo:todo' (lazy loading)
 * Environment: production
   WARNING: This is a development server. Do not use it in a production deployment.
   Use a production WSGI server instead.
 * Debug mode: off
Usage: python -m flask run [OPTIONS]
Try 'python -m flask run --help' for help.

Error: Could not import 'todo.todo'.

(venv) C:\routeproject>python

This is mi __init__.py file:

import os

from flask import Flask

def create_app():
app = Flask(__name__)

app.config.from_mapping(
    SECRET_KEY='mikey',
    DATABASE_HOST=os.environ.get('FLASK_DATABASE_HOST'),
    DATABASE_PASSWORD=os.environ.get('FLASK_DATABASE_PASSWORD'),
    DATABASE_USER=os.environ.get('FLASK_DATABASE_USER'),
    DATABASE=os.environ.get('FLASK_DATABASE'),
)

@app.route('/hola')
def hola():
    return 'Hola aplicación !'

    return app

How can i solve this please?