private static async IAsyncEnumerable <ApplicationUser> GetOrCreateUsers(this AppUserManager manager, GenderValue?gender, params string[] userNames) { foreach (var userName in userNames) { var user = new ApplicationUser(userName) { Id = GuidUtilities.Create($"u_{userName}").ToString(), Gender = gender, IsActive = true }; await manager.CreateOrUpdateByNameAsync(user, "Password123").ConfigureAwait(false); yield return(user); } }