It's like saying that . is used for full-stops and shouldn't be used for dot balls in this kata.

A little similar to Difference of 2.

Added input assertion messages on failure.

Thank you!

As the input is a string, it won't modify the input, that only happens with lists.

Too easy in python.

Description table is hard to see in light mode.

In python example test cases, for board =

[
    [1, 0, 0, 0, 0, 0, 0, 0],
    [0, 0, 0, 0, 0, 0, 0, 0],
    [0, -1, 0, 0, 1, 0, 0, 0],
    [0, 0, 0, 0, 0, 0, 0, 0],
    
    [0, 0, 0, 0, 0, 0, 0, 0],
    [0, 0, 0, -1, -1, 0, 0, 0],
    [0, 0, 0, 0, 0, 0, 0, 0],
    [0, 0, 0, 0, 0, 0, 0, 0]
]

It says 19 should equal 20, but have a look at this image and count the zeros (safe spots)

Awaiting Approval! Assessed ranks.

Thank you!

Example tests don't even test the function. Also, existing function sorted() pass all the tests. Initial solution has example of add_two_ages function.

Approved!