That's why I linked to Jeffries' post where he gave more context.

Though, in this particular case, he then went on to go back down the TDD Sudoku rabbit hole and, though he does seem to eventually write a program that works, the path to get there involved reading existing solutions and seems rather drain circly, which makes his post I linked seem a bit like making excuses. IDK. I don't really care beyond mild bemusement.

Haha, he really continued digging himself into the hole, i see it now.

"I’ve found some Python code for Sudoku techniques. I do not like it. But it’ll be useful, I reckon, even though we aren’t likely to copy it."