Overriding layered navigation block

I just want add a custom function in layered navigation block MagentoLayeredNavigationBlockNavigation

the function :

public function getActiveFilters()
{
   $filters = $this->getLayer()->getState()->getFilters();
   if (!is_array($filters)) {
        $filters = [];
   }
   return $filters;
}

ive tried to create custom module to override block with preferences as well as plugin, but no luck its not working.

at first try, im using preference. I use this code in

VendorModuleetcdi.xml

< ?xml version="1.0"?>

and create block in my custom module

< ?php
namespace VendorModuleBlock;

class Navigation extends MagentoLayeredNavigationBlockNavigation
{
    /**
     * Retrieve active filters
     *
     * @return array
     */
    public function getActiveFilters()
    {
        $filters = $this->getLayer()->getState()->getFilters();
        if (!is_array($filters)) {
            $filters = [];
        }
        return $filters;
    }
}

but its not working, as well as using plugin to override block.

am I missing something?
and what is the best way to override block?

Thanks in Advance.