RuntimeError: uvicorn is not installed. Please install connexion using the uvicorn extra (connexion[uvicorn])

The error message "RuntimeError: uvicorn is not installed. Please install connexion using the uvicorn extra (connexion[uvicorn])" indicates that you're trying to run a Python application using the Connexion framework, which depends on Uvicorn as the ASGI server for handling HTTP requests. Uvicorn is not currently installed in your system.

Here's what needs to be done:

1. First, you need to install Uvicorn if you haven't already. You can do this by running:

pip install uvicorn

2. Then, to install Connexion with the Uvicorn support, you should specify the `uvicorn` extra when installing Connexion:

pip install connexion[uvicorn]

This will install both Connexion and its required dependencies, including Uvicorn.

Once these steps are complete, you should be able to run your application using Uvicorn without encountering the `RuntimeError`.