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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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']