/**
  * @param $api_method
  * @param string $http_method
  * @param array $query_string
  * @param array $headers
  * @param string $content
  * @return QueryInterface
  */
 public function prepare($api_method, $http_method = 'GET', array $query_string = array(), $headers = array(), $content = '')
 {
     if (!$this->access_token) {
         $this->obtainBearerToken();
     }
     $query = new Query();
     $query->setApiMethod($this->normalizeApiMethod($api_method));
     $query->setHttpMethod($http_method);
     $query->setHeaders($this->getHeaders($headers));
     $query->setContent($content);
     $query->setQueryString($query_string);
     return $query;
 }