func selectDay(index: Int, isSelected: Bool) {
        let isBool = isSelected == false
        switch index {
        case 0:
            monday = isBool ? week[0] : ""
        case 1:
            tuesday = isBool ? week[1] : ""
        case 2:
            wednesday = isBool ? week[2] : ""
        case 3:
            thursday = isBool ? week[3] : ""
        case 4:
            friday = isBool ? week[4] : ""
        case 5:
            saturday = isBool ? week[5] : ""
        default:
            sunday = isBool ? week[6] : ""
        }
        days = monday + tuesday + wednesday + thursday + friday + saturday + sunday

func checkImageIsHidden(_ dayViewModel: PillDayViewModel, indexPath: IndexPath) {
        checkImage.isHidden.toggle()
        isSelected.toggle()
        dayViewModel.selectDay(index: indexPath.row, isSelected: checkImage.isHidden)
    }

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        guard let cell = tableView.cellForRow(at: indexPath) as? PillDayTableViewCell else { return }
        cell.checkImageIsHidden(viewModel, indexPath: indexPath)
    }

extension String {
    func addSeparator() -> String {
        let string = self.map{String($0)}
        let separator = string.joined(separator: ", ")
        return separator
    }
}