Fatal error: Uncaught exception 'Google_Exception' with message 'Unknown functio n: ->->insert()' I could'nt understand whats wrong in here...If anyone know clear this issue jz rply quickly.......

public function insert($postBody, $optParams = array())
  {
    $params = array('postBody' => $postBody);
    $params = array_merge($params, $optParams);
    return $this->call('insert', array($params), "Google_Service_Drive_DriveFile");
  }

public function call($name, $arguments, $expected_class = null)
  {
    if (! isset($this->methods[$name])) {
      throw new Google_Exception(
          "Unknown function: " .
          "{$this->serviceName}->{$this->resourceName}->{$name}()"
      );
    }