Drivers : Can a driver child access to siblings methods?

Greetings and thanks for your awesome work. I have an issue with CodeIgniter drivers! Let's suppose I have a driver named App and inside drivers folder I have App_child_one and App_child_two

Code:

App_child_one extends CI_Driver { ...} has method_one() {}

and

Code:

App_child_two extends CI_Driver { ...} has method_two() {}

How can I access App_child_two::method_two() from App_child_one  knowing that I have tried:

Code:

$this->CI->app->child_two->method_two()

 but I get this error:

Code:

Undefined property: CI::$app

Thanks in advance.

EDITED

I could access using:

PHP Code:

$this->_parent->driver 


But the class comes empty like it has no methods at all.

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