Magento 2 api for layer navigation filters available?

<?php

namespace handymustFilterModel;

use handymustFilterApiFilterInterface;
use MagentoCatalogModelLayerResolver;
use MagentoCatalogModelLayerCategoryFilterableAttributeList;
use MagentoCatalogModelLayerFilterList;
use MagentoFrameworkExceptionLocalizedException;

class Filter implements FilterInterface
{
    protected $layerResolver;
    protected $filterList;
    protected $filterableAttributeList;

    public function __construct(
        Resolver                $layerResolver,
        FilterList              $filterList,
        FilterableAttributeList $filterableAttributeList
    )
    {
        $this->layerResolver = $layerResolver;
        $this->filterList = $filterList;
        $this->filterableAttributeList = $filterableAttributeList;
    }

    /**
     * @throws LocalizedException
     */
    public function getByCategoryId($categoryId)
    {
        // Initialize layer and set the current category
        $layer = $this->layerResolver->get();
        $layer->setCurrentCategory($categoryId);

        // Get the list of filterable attributes for the current category
        $filterAttributes = $this->filterList->getFilters($layer);

        $filterValues = [];

        foreach ($filterAttributes as $filter) {
            $attributeCode = $filter->getRequestVar();
            $items = $filter->getItems();

            $filterValues[$attributeCode] = [];

            foreach ($items as $item) {
                $label = $item->getLabel();
                $count = $item->getCount();
                $value = $item->getValue();

                $filterValues[$attributeCode][] = [
                    'label' => $label,
                    'count' => $count,
                    'value' => $value,
                ];
            }
        }

        return $filterValues;
    }
}

errors are in the screenshot: