def set_fold_trigger(block, val):
        """
        Set the block fold trigger flag (True means the block is a fold
        trigger).

        :param block: block to set
        :param val: value to set
        """
        if block is None:
            return
        state = block.userState()
        if state == -1:
            state = 0
        state &= 0x7BFFFFFF
        state |= int(val) << 26
        block.setUserState(state)