def METHOD_NAME(self, schema: dict) -> Optional[str]:
    """Send a schema to the ledger."""
    try:
        response = requests.post(self.api_url + '/schemas',
                                 headers=self._get_headers(),
                                 data=json.dumps(schema))
        response.raise_for_status()
        return response.json()['schema_id']
    except Exception as err:
        self.app.logger.error(
            f"Failed to register digital credential schema {schema['schema_name']}:{schema['schema_version']}")
        self.app.logger.error(err)
        raise err