@swe: This seems like a recurring problem for you. One thing you may be missing is that just typing code into a cell doesn’t change anything, until you actually execute that cell by selecting it and then clicking “Shift-Enter” to run it. Just typing new code and then calling the function again will run the old code.
You can prove this to yourself really easily: take a function that works and test it by running the test cell that calls that function. All good. Now type a syntax error or in some other way break the function, but don’t hit “Shift-Enter” and then run your test cell again. It still works. Now click “Shift-Enter” in the broken cell and then try the test again.