/**
  * Shortcut method for creating a MemoizedCallable and invoking it
  * with the specified arguments.
  *
  * @param callable $callable
  * @param array $args
  * @param int $ttl
  */
 public static function call($callable, array $args = array(), $ttl = 3600)
 {
     $instance = new self($callable, $ttl);
     return $instance->invokeArgs($args);
 }