private async void AddRegistration(object sender, EventArgs e)
{
var apartment = new Apartment
{
LastName = LastName.Text,
StreetAddress = StreetAddress.Text,
PostalCode = int.Parse(PostalCode.Text)
};
Guid apartmentId = await _registrationService.AddApartment(apartment);
KeyValueStorage.SetApartmentId(apartmentId);
}