src/Sherlock/requests/SearchRequest.php
public function facets($facets)
    {
        $this->params['facets'] = array();
        if (is_array($facets)){
            $args = $facets;
        }else{
            $args = func_get_args();
        }
        foreach ($args as $arg) {
            if ($arg instanceof FacetInterface) {
                $this->params['facets'][] = $arg;
            }
        }

        return $this;
    }
public function facets($facets)
    {
        $this->params['facets'] = array();
        if (is_array($facets)){
            $args = $facets;
        }else{
            $args = func_get_args();
        }
        foreach ($args as $arg) {
            if ($arg instanceof FacetInterface) {
                $this->params['facets'][] = $arg;
            }
        }

        return $this;
    }
Sets the facets to operate on

@param  FacetInterface $facets     types to query
@param  FacetInterface $facets,... types to query

@return SearchRequest