How to use the stacker.exceptions.UnableToExecuteChangeSet function in stacker

status = response["Status"]
    if status == "FAILED":
        status_reason = response["StatusReason"]
        if "didn't contain changes" in response["StatusReason"]:
            logger.debug(
                "Stack %s did not change, not updating.",
                fqn,
            )
            raise exceptions.StackDidNotChange
        raise exceptions.UnhandledChangeSetStatus(
            fqn, change_set_id, status, status_reason
        )

    execution_status = response["ExecutionStatus"]
    if execution_status != "AVAILABLE":
        raise exceptions.UnableToExecuteChangeSet(fqn,
                                                  change_set_id,
                                                  execution_status)

    changes = response["Changes"]
    return changes, change_set_id

)
            cfn_client.delete_change_set(ChangeSetName=change_set_id)
            raise exceptions.StackDidNotChange()
        logger.warn(
            "Got strange status, '%s' for changeset '%s'. Not deleting for "
            "further investigation - you will need to delete the changeset "
            "manually.",
            status, change_set_id
        )
        raise exceptions.UnhandledChangeSetStatus(
            fqn, change_set_id, status, status_reason
        )

    execution_status = response["ExecutionStatus"]
    if execution_status != "AVAILABLE":
        raise exceptions.UnableToExecuteChangeSet(fqn,
                                                  change_set_id,
                                                  execution_status)

    changes = response["Changes"]
    return changes, change_set_id

)
            cfn_client.delete_change_set(ChangeSetName=change_set_id)
            raise exceptions.StackDidNotChange()
        logger.warn(
            "Got strange status, '%s' for changeset '%s'. Not deleting for "
            "further investigation - you will need to delete the changeset "
            "manually.",
            status, change_set_id
        )
        raise exceptions.UnhandledChangeSetStatus(
            fqn, change_set_id, status, status_reason
        )

    execution_status = response["ExecutionStatus"]
    if execution_status != "AVAILABLE":
        raise exceptions.UnableToExecuteChangeSet(fqn,
                                                  change_set_id,
                                                  execution_status)

    changes = response["Changes"]
    return changes, change_set_id

def __init__(self, stack_name, change_set_id, execution_status):
        self.stack_name = stack_name
        self.id = change_set_id
        self.execution_status = execution_status

        message = ("Changeset '%s' on stack '%s' had bad execution status: "
                   "%s" % (change_set_id, stack_name, execution_status))

        super(UnableToExecuteChangeSet, self).__init__(message)