/**
  * Sets an alternative endpoint to the default
  * 
  * @param  Zend_Uri_Http $endpoint
  * @return Zend_Service_Amazon_Ses
  * @throws InvalidArgumentException If the provided endpoint url is not valid
  */
 public function setEndpoint(Zend_Uri_Http $endpoint)
 {
     $this->_endpoint = $endpoint;
     if (!$endpoint->valid()) {
         throw new InvalidArgumentException(sprintf('The provided url "%s" is not valid.', $endpoint->getUri()));
     }
     return $this;
 }