How to debug a Python loop-condition bug

You are given a Python script that appears to hang or produce incorrect results because of a bug in a loop condition (for example, the termination logic of a while or for loop).

Explain how you would debug it systematically to find the faulty loop condition and fix it. Include:

• the tools and techniques you would use (such as prints, logging, a debugger, and unit tests), and
• the common loop-condition mistakes you would check for.