some testing ang enchancments

map.go

@@ -34,6 +34,20 @@ func (m HashMap[K, V]) Contains(key K) bool {
 	_, ok := m[key]
 	return ok
 }
+func (m HashMap[K, V]) Keys() []K {
+	keys := make([]K, 0, m.Len())
+	for k := range m {
+		keys = append(keys, k)
+	}
+	return keys
+}
+func (m HashMap[K, V]) Values() []V {
+	values := make([]V, 0, m.Len())
+	for _, v := range m {
+		values = append(values, v)
+	}
+	return values
+}
 func (m HashMap[K, V]) Filter(f func(K, V) bool) HashMap[K, V] {
 	out := make(HashMap[K, V])
 	for k, v := range m {