TwoKeyMap
class TwoKeyMap<K1, K2, V> { }
_map: Map<K1, Map<K2, V>>;
delete(key1: K1, key2: K2): boolean;
deleteTop(key1: K1): boolean;
get(key1: K1, key2: K2): V | undefined;
getFallback(
key1: K1,
key2: K2,
fallback: V,
): V;has(key1: K1, key2: K2): boolean | undefined;
map<T>(fn: (
v: V,
k1: K1,
k2: K2,
) => T): T[];set(
key1: K1,
key2: K2,
value: V,
): this;