// MARK : Filtering methods
fileprivate func filter() {

  resultsList = []

    for i in 0 ..< dataList.count {

        let item = dataList[i]

        let cityFilterRange = (item.cityName as NSString).range(of: text!, options: .caseInsensitive)
        let countryFilterRange = (item.countryName as NSString).range(of: text!, options: .caseInsensitive)

        if cityFilterRange.location != NSNotFound {
            item.attributedCityName = NSMutableAttributedString(string: item.cityName)
            item.attributedCountryName = NSMutableAttributedString(string: item.countryName)

            item.attributedCityName!.setAttributes([.font: UIFont.boldSystemFont(ofSize: 17)], range: cityFilterRange)
            if countryFilterRange.location != NSNotFound {
                item.attributedCountryName!.setAttributes([.font: UIFont.boldSystemFont(ofSize: 17)], range: countryFilterRange)
            }
            resultsList.append(item)
        }
    }
    tableView?.reloadData()
 }