Returns the list of labels on a piece of Content.
        :param page_id: A string containing the id of the labels content container.
        :param prefix: OPTIONAL: The prefixes to filter the labels with {@see Label.Prefix}.
                                Default: None.
        :param start: OPTIONAL: The start point of the collection to return. Default: None (0).
        :param limit: OPTIONAL: The limit of the number of labels to return, this may be restricted by
                            fixed system limits. Default: 200.
        :return: The JSON data returned from the content/{id}/label endpoint, or the results of the
                 callback. Will raise requests.HTTPError on bad input, potentially.

def get_page_labels(self, page_id, prefix=None, start=None, limit=None):
        """
        Returns the list of labels on a piece of Content.
        :param page_id: A string containing the id of the labels content container.
        :param prefix: OPTIONAL: The prefixes to filter the labels with {@see Label.Prefix}.
                                Default: None.
        :param start: OPTIONAL: The start point of the collection to return. Default: None (0).
        :param limit: OPTIONAL: The limit of the number of labels to return, this may be restricted by
                            fixed system limits. Default: 200.
        :return: The JSON data returned from the content/{id}/label endpoint, or the results of the
                 callback. Will raise requests.HTTPError on bad input, potentially.
        """
        url = 'rest/api/content/{id}/label'.format(id=page_id)
        params = {}
        if prefix:
            params['prefix'] = prefix
        if start is not None:
            params['start'] = int(start)
        if limit is not None:
            params['limit'] = int(limit)
        return self.get(url, params=params)