if level2 == null then return
level2.keys.remove(k2)
end
+
+ # Remove all items
+ fun clear do level1.clear
end
# Simple way to store an `HashMap[K1, HashMap[K2, HashMap[K3, V]]]`
if level2 == null then return
level2.remove_at(k2, k3)
end
+
+ # Remove all items
+ fun clear do level1.clear
end
# A map with a default value.