Thank you so much for your kind reply. However, I believe I dont have the proper grasp of translations. I will try reading docs and get back to this. Cheers !!

Turns out type aliases are not even available in Python 3.11, which is what we have here .. :[

fixed

Java translation is also facing issues 2, 3, (probably 5), 6.

Replaced with tuple[tuple[str, ...], ...]

Frankly, the more types you can take out of the function definition itself, the better. I'm used to signatures on a separate line ( Haskell ) and I much prefer that over the incredibly busy Python syntax ( I think I've seen similar in what may have been Java, and I hate it ).

This

type Piece = Literal[ 'X', 'O', '_' ]
type Row   = tuple[ Piece, Piece, Piece ]
type Board = tuple[ Row, Row, Row ]
type Boolean = bool

def is_valid(board: Board) -> Boolean:

is quite enough clutter for me; I need to be able to see what arguments a function takes.
Python not being consistent with its naming convention for types ( why is Literal capitalised but tuple isn't? ) is not helping differentiate variables and types either.

But wouldn't its multiline nature distract the solver?

I quite like the second option actually. Reasonably concise, and very exact.

Removed.

That app took it from Battleship, which was produced by Milton-Bradley starting in 1967.

I’m not entirely sure, to be honest.

As I recently mentioned on discord, I changed my mind. Do what you think is the best

fixed