Checksum (dat002.edf) generation for the credits file (dat001.edf) from Endless Online.

endless_credits_checksum.py

from pathlib import Path

def generate_checksum(dat001: Path) -> str:
  file_size = dat001.stat().st_size
  
  aeo_count = 0
  with open(dat001, 'r') as file:
    for character in file.read():
      if character in ['a', 'A', 'e', 'E', 'o', 'O']:
        aeo_count = aeo_count + 1
  
  return f"DAT001.ID{{{file_size * 3013 - 11}:145:{aeo_count}:{file_size * 21}}}"