Symfony2 passing values to collection form type

Question

I have the following entity relations:

• A Customer has one-to-many Address
• An Address has many-to-one County and many-to-one City
• A County has

Answer 1

in symfony3 :

$builder->add('example', CollectionType::class, array(
    'entry_type'   => ExampleType::class,
    'entry_options'  => array(
        'my_custom_option'  => true),
));