public async Task <string> AdminSignUp(string username, string password, string phone) { if (username == null) { return("username cannot be null"); } if (await usersDAL.AddDataUser(new RegisteredAdmin(username, EncryptString(key, password), phone))) { await usersDAL.AddNewAdminState(username, EncryptString(key, password), phone); await usersDAL.AddNewShoppingCart(username); return("success"); } return("username: "******" is already taken please choose a different one"); }