How to create a mob with custom ai?

With Bukkit and Spigot you do that by making a superclass extend from the EntityClass then editing custom pathfinder goals and all that stuff. Is there a similar way to do that here?

 

There is completely no ai in pocketmine, you will have to write your own ai

 

But it is possible so how

 

You might want to look at how https://github.com/RevivalPMMP/PureEntitiesX/tree/master/ does it or modify it.