@classmethod
    def _isLevel(cls, filename):

        if os.path.exists(os.path.join(filename, "chunks.dat")):
            return False  # exclude Pocket Edition folders

        if not os.path.isdir(filename):
            f = os.path.basename(filename)
            if ("level.dat", "level.dat_old") not in f:
                return False
            filename = os.path.dirname(filename)

        files = os.listdir(filename)
        if "level.dat" in files or "level.dat_old" in files:
            return True

        return False

    # --- Dimensions ---
dataset/ETHPy150Open mcedit/pymclevel/infiniteworld.py/MCInfdevOldLevel._isLevel/swapped operands of `not in`