I am writing a small chess GUI with Python chess library. Yesterday, I ran my code a lot of times without any problem. Then I installed some other Python libraries. Today I noticed a strange mistake: board.legel_moves generates wrong moves. I tried to reinstall Python 3.13.1 and the latest Python chess library, the mistake still exists.

I am writing a small chess GUI with Python chess library. Yesterday, I ran my code a lot of times without any problem. Then I installed some other Python libraries. Today I noticed a strange mistake: board.legel_moves generates wrong moves. I tried to reinstall Python 3.13.1 and the latest Python chess library, the mistake still exists.

I am writing a small chess GUI with Python chess library. Yesterday, I ran my code a lot of times without any problem. Then I installed some other Python libraries. Today I noticed a strange mistake: board.legel_moves generates wrong moves. I tried to reinstall Python 3.13.1 and the latest Python chess library, the mistake still exists.

I am writing a small chess GUI with Python chess library. Yesterday, I ran my code a lot of times without any problem. Then I installed some other Python libraries. Today I noticed a strange mistake: board.legel_moves generates wrong moves. I tried to reinstall Python 3.13.1 and the latest Python chess library, the mistake still exists.

I am writing a small chess GUI with Python chess library. Yesterday, I ran my code a lot of times without any problem. Then I installed some other Python libraries. Today I noticed a strange mistake: board.legel_moves generates wrong moves. I tried to reinstall Python 3.13.1 and the latest Python chess library, the mistake still exists.

PGN with scores like this:

I have proceeded a bit with my goal to obtain a chess-game endgame engine where both players would play fully optimally while there are D<5 pieces on the board so that I can wait for the result.The player who can give a checkmate (be it B or W) should give it as soon as possible while the player who gets inevitably checkmated delays it as long as possible. Draw should be treated reasonably as well. I have obtained this code: https://pastebin.com/FKugyrXW which does 100% this: it computes the minimal number of plies between 2 fen strings which are both descendants of a given initial_fen string. However I’m unable to extract from that functionality the optimal move, it says c1c8 which is not true, c1c6 is OK here,please see the bottom of this page: https://pastebin.com/x8CZ5FwS
Should anyone be interested in a small amount of money for fixing this, contact me at LinkedIn, the name is Jan Pax.The code is included for convenience:

I have proceeded a bit with my goal to obtain a chess-game endgame engine where both players would play fully optimally while there are D<5 pieces on the board so that I can wait for the result.The player who can give a checkmate (be it B or W) should give it as soon as possible while the player who gets inevitably checkmated delays it as long as possible. Draw should be treated reasonably as well. I have obtained this code: https://pastebin.com/FKugyrXW which does 100% this: it computes the minimal number of plies between 2 fen strings which are both descendants of a given initial_fen string. However I’m unable to extract from that functionality the optimal move, it says c1c8 which is not true, c1c6 is OK here,please see the bottom of this page: https://pastebin.com/x8CZ5FwS
Should anyone interested in small amount of money for fixing this, contact me at LinkedIn, the name is Jan Pax.The code is included for convenience: