src/DependencyInjection/SilverStripe/HeystackSilverStripeContainerBuilder.php
public function has($id)
    {
        if ($this->isSilverStripeServiceRequest($id)) {
            return (bool) $this->getSilverStripeService($id);
        } else {
            return parent::has($id);
        }
    }
public function has($id)
    {
        if ($this->isSilverStripeServiceRequest($id)) {
            return (bool) $this->getSilverStripeService($id);
        } else {
            return parent::has($id);
        }
    }
public function has ( $ id ) { if ( $ this -> isSilverStripeServiceRequest ( $ id ) ) { return ( bool ) $ this -> getSilverStripeService ( $ id ) ; } else { return parent :: has ( $ id ) ; } }
Return true if the service requested is a SilverStripe service and it exists in the SS container

@param  string $id
@return bool
Return true if the service requested is a SilverStripe service and it exists in the SS container