I use PySnooper[1] when code behavior deviates inscrutably from my mental model. Like Icecream, PySnooper exhorts, "Never use print for debugging again." A simp

I use PySnooper[1] when code behavior deviates inscrutably from my mental model. Like Icecream, PySnooper exhorts, "Never use print for debugging again." A simple example: import pysnooper @pysnooper.snoop() def add_up(numbers): total = 0 for number in numbers: total += number return total add_up([123, 456]) When run, PySnooper prints the activity of the decorated function or method: $ python example.py Source path:... /home/joel/example.py Starting var:.. numbers = [123, 456] 08:46:58.742543 call 4 def add_up(numbers): 08:46:58.742692 line 5 total = 0 New var:....... total = 0 08:46:58.742722 line 6 for number in numbers: New var:....... number = 123 08:46:58.742755 line 7 total += number Modified var:.. total = 123 08:46:58.742787 line 6 for number in numbers: Modified var:.. number = 456 08:46:58.742818 line 7 total += number Modified var:.. total = 579 08:46:58.742847 line 6 for number in numbers: 08:46:58.742876 line 8 return total 08:46:58.742898 return 8 return total Return value:.. 579 Elapsed time: 00:00:00.000405 [1] https://github.com/cool-RR/PySnooper https://github.com/cool-RR/PySnooper