In the solution of Exercise 1, there it is said to first remove one line which is diplayed. And then it is said
And the lines:
which implies that the displayed lines should be removed, but in fact the displayed lines should remain.
In the final solution box for the exercise 1, the full code block is given. However, this block code already includes the solution for the TODO 5 which confuses the reader and spoils the solution for it.