public function installed( $name )
	{
		if( ! is_array($name) )
		{
			$name = [$name];
		}

		if( ! count($name) )
		{
			return false;
		}

		foreach( $name as $module_name )
		{
			if( is_numeric($module_name) )
			{
				if( !$this->offsetExists($module_name) )
				{
					return false;
				}
			}
			else if( $this->getId($module_name) === false )
			{
				return false;
			}
		}

		return true;
	}