private function getHttpVerb($webdriver_command)
    {
        $methods = $this->getMethods();

        if (!isset($methods[$webdriver_command])) {
            throw new E5xx_BadMethodCallWebDriverError(sprintf(
                '%s is not a valid webdriver command.',
                $webdriver_command
            ));
        }

        // the first element in the array is the default HTTP verb to use
        return $methods[$webdriver_command];
    }