Cartalyst\Stripe\ConfigInterface::setApiKey PHP Method

    public function setApiKey($apiKey);

 /**
  * Sets the Stripe API key.
  *
  * @param  string  $apiKey
  * @return $this
  */
 public function setApiKey($apiKey)
 {
     $this->config->setApiKey($apiKey);
     return $this;
 }