Why can't I call my array with in a IBAction function but in a normal function?

I can call scheduleCellEntries[indexPath.row] in the cellForRowAtfunction but in the @IBAction function that is linked to a button it's not possible that way.

When I run the code I get the following error: Use of unresolved identifier 'indexPath'; did you mean 'IndexPath'?

I tried to do do it the same way as recommended in the error, but that didn't work either.

Array:

var scheduleCellEntries: [ScheduleCell]! = [ScheduleCell(id: 1, textButtonState: false, timeButtonState: false, text: "Appointment", time01: "07:30", time02: "12:30")

cellForRowAt Function:

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        if tableView == scheduleTableView {

                let cell = tableView.dequeueReusableCell(withIdentifier: "scheduleCell", for: indexPath) as! scheduleTableViewCell


            if scheduleCellEntries[indexPath.row].timeButtonState == false{
                cell.scheduleDateCheckBox.isSelected = false

            }else{
                cell.scheduleTextCheckBox.isSelected = true

            }

            if scheduleCellEntries[indexPath.row].textButtonState == false{
                cell.scheduleTextCheckBox.isSelected = false

            }else{
                cell.scheduleTextCheckBox.isSelected = true

            }

                return cell
}

@IBActionFunction:

@IBAction func timeCheckboxIsPressed(_ sender: UIButton) {

        if sender.isSelected {
            sender.isSelected = false
            scheduleCellEntries[indexPath.row].timeButtonState = false

        } else {
            sender.isSelected  = true
            scheduleCellEntries[indexPath.row].timeButtonState = true
        }

    }

I would like to assess the array in that function so that whenever the button state is switched, the boolean value in the array changes as well.