Best door locks for baby?

Question

I have bad anxiety over our baby being at our parents houses since both have pools. I want to make sure they do all they can to prevent a bad accident from happening. 
What door locks are best to make sure baby can’t easily open the doors?

Answer

Those white plastics things that go over the knobs are nice. Otherwise you know the chain ones that come on doors that like slide through a metal piece and then come out of the round part? Those work too.

Answer

The chain thingy at the top of the door is the best, or a slider lock at the top of the door where they cant reach, or even a deadbolt thats higher up that they cant reach, if you go with a chain lock make sure the chain is a very short chain, there are some chains sold that are longer that a child can fit through the crack it leaves between the door opening and the chain stopping it so make sure you get a very short chain, kids have small heads and are smushable, so get a small short chain, i like the slider locks because they cant undoo them, and theres no risk of them slipping through the gap