public async Task <string> GetSubRegionIsoIds(string sub_key)
{
string isoID;
if (HasSubDivisionsIsoId)
{
var isoids = this.GetAllSubRegionIsoIds().ToArray();
var index = GetSubRegionsKeys().ToList().IndexOf(sub_key);
isoID = isoids[index];
}
else
{
isoID = await AddressData.GetSubDivisionIsoID(this.Key, sub_key);
}
return(isoID);
}