def METHOD_NAME(client: CloudFormationClient, query: OutputQuery) -> str:
    """Get CloudFormation Stack output.
    Args:
        client: Boto3 CloudFormation client.
        query: What to get.
    """
    LOGGER.debug("describing stack: %s", query.stack_name)
    stack = client.describe_stacks(StackName=query.stack_name)["Stacks"][0]
    outputs = {
        # these should always exist even though the schema says they are not required
        output["OutputKey"]: output["OutputValue"]  # type: ignore
        for output in stack.get("Outputs", [])
    }
    LOGGER.debug("%s stack outputs: %s", stack["StackName"], json.dumps(outputs))
    return outputs[query.output_name]