This may not fit your way of looking at this problem but please, read on. One of the most fun things about python, or any terse loose language, is that you can

This may not fit your way of looking at this problem but please, read on. One of the most fun things about python, or any terse loose language, is that you can now write amazingly massive amounts of code without having to do exhaustive checking as you go. For example, in C, a non-expert will often end up having to write tons of tiny functions, recompiling, and testing _constantly_ in order to avoid the hell that is having written a large chunk of code containing one tiny error and not being able to find that error even after hours of debugging. Just the other day I reimplemented a rather large network protocol coded in C into ~1500 lines of python all at once. When it was done I decided, with some trepidation, to just run the whole thing and see what happens. It worked! Soon after, my test code did find one small type error in an obscure edge part of the code, but the good feeling from getting the immediate success didn't go away! So the bad practice is not having tests/asserts anyway -- regardless of whether your language has type checking. He is right that just running as much as possible can be much more encouraging and even FUN, for beginners especially.