public function has($key)
	{
		if (count(func_get_args()) > 1)
		{
			foreach (func_get_args() as $value)
			{
				if ( ! $this->has($value)) return false;
			}

			return true;
		}

		if (is_bool($this->input($key)) || is_array($this->input($key)))
		{
			return true;
		}

		return trim((string) $this->input($key)) !== '';
	}