public static bool contains <K, V>(HMap <K, V> map, Tuple <K, V> kv) => map.Contains(kv.Item1, kv.Item2);
public static bool contains <K, V>(HMap <K, V> map, KeyValuePair <K, V> kv) => map.Contains(kv.Key, kv.Value);
public static bool contains <K, V>(HMap <K, V> map, Tuple <K, V> kv) => map.Contains(kv.Item1, kv.Item2);
public static bool contains <K, V>(HMap <K, V> map, KeyValuePair <K, V> kv) => map.Contains(kv.Key, kv.Value);