def _isLevel(cls, filename):
        clp = ("chunks.dat", "level.dat")

        if not os.path.isdir(filename):
            f = os.path.basename(filename)
            if f not in clp:
                return False
            filename = os.path.dirname(filename)

        return all([os.path.exists(os.path.join(filename, fl)) for fl in clp])