* Collect the money from the client.
    * Send a notification back to the API user (the external developer), as a callback.
        * At this point is that the API will somehow send a POST request to the
            external API with the notification of the invoice event
            (e.g. "payment successful").
    """
    # Send the invoice, collect the money, send the notification (the callback)
    return {"msg": "Invoice received"}

                    "operationId": "create_invoice_invoices__post",

* Update GitHub action issue-manager. PR [#1520](https://github.com/tiangolo/fastapi/pull/1520).
* Add new links:
    * **English articles**:
        * [Real-time Notifications with Python and Postgres](https://wuilly.com/2019/10/real-time-notifications-with-python-and-postgres/) by [Guillermo Cruz](https://wuilly.com/).