How to extend parent theme sections and settings to Options Tree

Question

For anyone who want to achieve the same thing :

add_filter( ot_settings_id() . '_args', 'my_ot_setting');

function my_ot_setting($custom_settings){

//do some work with the settings and the sections, ie append your settings.

return $custom_settings;
}

This works if the parent theme applies this filter before saving the options like the example here : https://github.com/valendesigns/option-tree-theme/blob/master/inc/theme-options.php#L833

Otherwise you have to do it yourself like the example above.