Create a fab launch function in fabfile.py to perform the following actions:

• Given a build variant, spawn a new Evergreen and/or AWS instance and install the testy framework. We would want a pre-defined set of build variants that the user can select from to pass in as input.
  • If AWS is chosen, the run-instances command should be useful.

• Given a testy backup snapshot id, create a new instance in AWS and a new volume from the snapshot, attach and mount the volume to the instance.

The function should print the necessary information for the user to log into the new instance on success, and an error message on failure.