isShebaValid method
Implementation
bool isShebaValid(String sheba) {
if (sheba.length != 26) return false;
if (!RegExp(r'IR[0-9]{24}').hasMatch(sheba)) return false;
final d1 = sheba.codeUnitAt(0) - 65 + 10;
final d2 = sheba.codeUnitAt(1) - 65 + 10;
var iban = sheba.substring(4);
iban += '$d1$d2${sheba.substring(2, 4)}';
final remainder = _iso7064Mod97_10(iban);
return remainder != 1 ? false : true;
}