def get_authorize_url(self, callback_url, state=None):
        """
        Returns the Authorize URL as returned by QB, and specified by OAuth 2.0a.
        :return URI:
        """
        auth_service = OAuth2Service(
            name='quickbooks',
            client_id=self.client_id,
            client_secret=self.client_secret,
            authorize_url=self.authorize_url,
            access_token_url=self.access_token_url,
            base_url=self.base_url,
        )

        params = {
            'client_id': self.client_id,
            'response_type': 'code',
            'scope': 'com.intuit.quickbooks.accounting',
            'redirect_uri': callback_url,
            'state': state,
        }

        url = auth_service.get_authorize_url(**params)

        return url
Returns the Authorize URL as returned by QB, and specified by OAuth 2.0a.
        :return URI: