Q: How to use ApproximateTimeSynchronizer in Python?
Original question: https://answers.ros.org/question/81126/how-to-use-approximatetime-in-python/

Q: How to check that two topics are synced?
Original question: https://answers.ros.org/question/274858/how-to-check-that-two-topics-are-synced/

A: Here you can see a very simple script that uses ApproximateTimeSynchronizer in Python.