read onlyDIFFICULTY_EASY:Difficulty
read onlyDIFFICULTY_HARD:Difficulty
read onlyDIFFICULTY_INVALID:Difficulty
read onlyDIFFICULTY_MEDIUM:Difficulty
read onlyDIFFICULTY_PASSIVE:Difficulty
read onlyDIFFICULTY_UNFAIR:Difficulty