def deleted_genes_to_reactions(model, genes):
    """ Convert a set of deleted genes to the respective deleted reactions.

    Arguments:
        model (CBModel): model
        genes (list): genes to delete

    Returns:
        list: list of deleted reactions
    """

    if isinstance(genes, str):
        genes = [genes]

    active_genes = set(model.genes) - set(genes)
    active_reactions = model.evaluate_gprs(active_genes)
    inactive_reactions = set(model.reactions) - set(active_reactions)

    return inactive_reactions