Services.xml file:

```
<?xml version="1.0" ?>

    <container xmlns="http://symfony.com/schema/dic/services"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">  

        <services>
            <service id="task.task_history_insertion" class="Acme\Bundle\EventListener\TaskHistoryInsertion">
                <argument type="service" id="service_container" />
                <tag name="doctrine.event_listener" event="postPersist" method="postPersist"/>
            </service>
        </services>
    </container>

```

TaskHistoryInsertion.php

```
class TaskHistoryInsertion implements EventSubscriber
{

    protected $container;
public function __construct(ContainerInterface $container)
{
    $this->container = $container; 
}

public function getSubscribedEvents()
{
    return array(
        Event::postPersist
    );
}

public function postPersist(LifecycleEventArgs $args)
{
         //not being called
        }
}

```

Any ideas on why postPersist isn't being called after persisting?