The Heroku Platform
Heroku is a popular PaaS. We can deploy our APIs there so that they can be accessed by anyone in the world. And it doesn't just support Python, but also other programming languages, including Ruby and Go.
Heroku provides a free plan for developers to deploy and test their applications there. Certainly, they do have paid plans as well, and with many more powerful functions that can make our APIs more secure and efficient. Later on, if you need these powerful features and system resources for your application, you can consider that. But right now, for teaching purposes, a free plan is good enough.
Apart from Heroku, there are other cloud service providers. Some of the market leaders in cloud services are Amazon Web Services (AWS), Google Cloud Platform (GCP), IBM Cloud, Microsoft Azure, and Rackspace Cloud.