docs: def delete_property(self, content_id, property_key, callback=None):
          """
          Deletes a content property.
          :param content_id (string): The ID for the content that owns the property to be deleted.
          :param property_key (string): The name of the property to be deleted.
          :param callback: OPTIONAL: The callback to execute on the resulting data, before the method returns.
                           Default: None (no callback, raw data returned).
          :return: Empty if successful, or the results of the callback.
                   Will raise requests.HTTPError on bad input, potentially.
          """
          return self._service_delete_request("rest/api/content/{id}/property/{key}"
                                              "".format(id=content_id, key=property_key), callback=callback)