/**
  * Set client
  *
  * @param  \OAuth2\ServerBundle\Entity\Client $client
  * @return ClientPublicKey
  */
 public function setClient(\OAuth2\ServerBundle\Entity\Client $client = null)
 {
     $this->client = $client;
     // this is necessary as the client_id is the primary key
     $this->client_id = $client->getClientId();
     return $this;
 }