This tool fixes player name casing in PGN files. It solves the problem where the same name with different casing might lead a player being identified as different players.

Create and activate a virtual environment with:

python3 -m venv .venv
source .venv/bin/activate

Install the chess package:

pip install chess

Running the script will fix all the PGN files in the current directory and it will output the new contents to the console. The output will merge the contents for all the input files.

mkdir result
python fixpgn.py > result/db.pgn

NOTE: it is important to store the resulting file in a different directory than the current one.