/**
 * Enumerates valid C0 standards
 */
export declare type Lang = "L1" | "L2" | "L3" | "L4" | "C0" | "C1";
/**
 * Accept strings like ".L1", "l1", "L1", and ".l1" and turn them into "L1"
 */
export declare function parse(s: string): Lang | null;