A Python script uses the GitHub and Twilio APIs to send notifications via SMS when new pull requests are submitted. The script creates a class called `PullNotifs` that authenticates with GitHub and Twilio, collects all repos and their number of pull requests, checks for new pull requests, and sends a notification if one is found. The script uses an object-oriented approach and includes methods to get all repos, set the number of pull requests, check for new pull requests, and send notifications. The script can be run in a loop to continuously monitor pull requests and send notifications as needed. With this script, developers can stay on top of their GitHub pull requests and receive notifications via SMS when new ones are submitted.