def METHOD_NAME(flow_name, add_optimizers=None, remove_optimizers=None):
    """Add or remove optimizers to/from an existing flow.
    Args:
        flow_name (str): The name of the flow to update.
        add_optimizers (list, optional): List (str) of optimizers to add. Defaults to None.
        remove_optimizers (list, optional): List (str) of optimizers to remove. Defaults to None.
    """
    flow = get_flow(flow_name)
    if add_optimizers is not None:
        for opt in add_optimizers:
            flow._add_optimizer(opt)
    if remove_optimizers is not None:
        for opt in remove_optimizers:
            flow._remove_optimizer(opt)