public static function count($countable, $count, $message = null, $propertyPath = null)
{
if ($count !== count($countable)) {
$message = sprintf($message ?: 'List does not contain exactly "%d" elements.', static::stringify($count));
throw static::createException($countable, $message, static::INVALID_COUNT, $propertyPath, array('count' => $count));
}
return true;
}