Validation in the Model not working

Hi all,
I am trying to perform data validation in my Model class, following along with the instruction/practices mentioned in the docs here. I am getting the error: 

PHP Code:

Call to a member function setRules() on null 


 

You have overridden the model constructor.
The model constructor already defines the $db property. And you can get access to QueryBuilder by calling the $this->builder() method.
If you still need a class constructor, then call the parent's constructor.