public void AuthorizeRequestToken(string requestToken, User user)
        {
            if (requestToken == null) {
                throw new ArgumentNullException("requestToken");
            }
            if (user == null) {
                throw new ArgumentNullException("user");
            }

            var tokenRow = Global.DataContext.OAuthTokens.SingleOrDefault(
                tokenCandidate => tokenCandidate.Token == requestToken &&
                tokenCandidate.State == TokenAuthorizationState.UnauthorizedRequestToken);
            if (tokenRow == null) {
                throw new ArgumentException();
            }

            tokenRow.State = TokenAuthorizationState.AuthorizedRequestToken;
            tokenRow.User = user;
        }
 partial void DeleteUser(User instance);
 partial void UpdateUser(User instance);
 partial void InsertUser(User instance);