verify abstract method
      
Future<AuthenticationResponse> 
verify({ 
    
- required DeliveryMethod method,
 - required String loginId,
 - required String code,
 
Verifies an OTP code sent to the user.
Provide this functions with the loginId and method of delivery used to
send the code. Upon successful authentication an AuthenticationResponse is returned.
Implementation
Future<AuthenticationResponse> verify({required DeliveryMethod method, required String loginId, required String code});