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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 _check_load_existing_object(self, object_type, id_field_name, operation='update'):
 # type: (str, str, str) -> None """Check metadata exists and contains HDX object identifier, and if so load HDX object Args: object_type (str):
 Description of HDX object type (for messages) id_field_name (str):
 Name of field containing HDX object identifier operation (str):
 Operation to report if error. Defaults to update. Returns: None """

        self._check_existing_object(object_type, id_field_name)
        if not self._load_from_hdx(object_type, self.data[id_field_name]):
            raise HDXError('No existing %s to %s!' % (object_type, operation))