Best way to pass function from MY_Controller to Controller

Hello I would like to know what the best way is to pass a function from MY_Controller to A Controller?

PHP Code:

<?php

class MY_Controller extends CI_Controller {

    protected $data = array();

    public function __construct() {
        parent::__construct();
        $this->load->model('design/model_layout');
        $this->load->model('extension/model_module');

        $this->column_left();
        $this->column_right();
        $this->content_top();
        $this->content_bottom();
        $this->footer();
        $this->header();
    }

    public function content_top() {
        
    }
} 


So I can do this on multiple controllers

PHP Code:

<?php

class Welcome extends MY_Controller {

    //public $data = array();

    public function __construct() {
        parent::__construct();
        $this->load->library('position');
    }

    public function index() {
        $data['column_left'] = $this->column_left();
        $data['column_right'] = $this->column_right();
        $data['content_top'] = $this->content_top();
        $data['content_bottom'] = $this->content_bottom();
        $data['footer'] = $this->footer();
        $data['header'] = $this->header();


        $this->load->view('home', $data);
    }
} 


There's only one rule - please don't tell anyone to go and read the manual.  Sometimes the manual just SUCKS!