Retrieves a new page of features from Geopedia

def _fetch_features(self):
        """ Retrieves a new page of features from Geopedia
        """
        if self.next_page_url is None:
            return

        response = get_json(self.next_page_url, post_values=self.query, headers=self.gpd_session.session_headers)

        self.features.extend(response['features'])
        self.next_page_url = response['pagination']['next']
        self.layer_size = response['pagination']['total']