diff --git a/docs/index.rst b/docs/index.rst
index 07470be..161c751 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -89,3 +89,11 @@ Storage
 -------
 
 ...
+
+Persistence
+~~~~~~~~~~~
+
+.. note:: 
+
+    Describe special actions required with PHPCR-ODM when persisting documents
+    with collection mappings.
diff --git a/src/Storage/Doctrine/PhpcrOdm/CollectionIdentifierUpdater.php b/src/Storage/Doctrine/PhpcrOdm/CollectionIdentifierUpdater.php
index d362632..8a7e4c0 100644
--- a/src/Storage/Doctrine/PhpcrOdm/CollectionIdentifierUpdater.php
+++ b/src/Storage/Doctrine/PhpcrOdm/CollectionIdentifierUpdater.php
@@ -2,14 +2,11 @@
 
 namespace Psi\Component\ContentType\Storage\Doctrine\PhpcrOdm;
 
-use Doctrine\Common\EventSubscriber;
-use Doctrine\Common\Persistence\Event\LifecycleEventArgs;
 use Doctrine\Common\Util\ClassUtils;
+use Doctrine\ODM\PHPCR\DocumentManagerInterface;
 use Doctrine\ODM\PHPCR\Event;
 use Metadata\MetadataFactory;
 use Metadata\MetadataFactoryInterface;
-use Psi\Component\ContentType\Storage\Doctrine\PhpcrOdm\PropertyEncoder;
-use Doctrine\ODM\PHPCR\DocumentManagerInterface;
 
 /**
  * The collection identifier updater updates the IDs (paths) of any documents
@@ -79,4 +76,3 @@ public function update(DocumentManagerInterface $documentManager, $document)
         }
     }
 }
-
diff --git a/src/Storage/Doctrine/PhpcrOdm/Subscriber/CollectionSubscriber.php b/src/Storage/Doctrine/PhpcrOdm/Subscriber/CollectionSubscriber.php
index 0a1b08d..c434e2a 100644
--- a/src/Storage/Doctrine/PhpcrOdm/Subscriber/CollectionSubscriber.php
+++ b/src/Storage/Doctrine/PhpcrOdm/Subscriber/CollectionSubscriber.php
@@ -4,14 +4,14 @@
 
 use Doctrine\Common\EventSubscriber;
 use Doctrine\Common\Persistence\Event\LifecycleEventArgs;
+use Doctrine\Common\Persistence\Event\ManagerEventArgs;
 use Doctrine\Common\Util\ClassUtils;
 use Doctrine\ODM\PHPCR\Event;
+use Doctrine\ODM\PHPCR\Mapping\ClassMetadata;
 use Metadata\MetadataFactory;
 use Metadata\MetadataFactoryInterface;
-use Psi\Component\ContentType\Storage\Doctrine\PhpcrOdm\PropertyEncoder;
-use Doctrine\ODM\PHPCR\Mapping\ClassMetadata;
-use Doctrine\Common\Persistence\Event\ManagerEventArgs;
 use PHPCR\Util\PathHelper;
+use Psi\Component\ContentType\Storage\Doctrine\PhpcrOdm\PropertyEncoder;
 
 /**
  * This class provides exception messages for cases when the collection
@@ -37,7 +37,7 @@ public function getSubscribedEvents()
     {
         return [
             Event::prePersist,
-            Event::preFlush
+            Event::preFlush,
         ];
     }
 
@@ -101,7 +101,7 @@ public function prePersist(LifecycleEventArgs $args)
             if (!isset($ctMetadata->propertyMetadata[$childrenField])) {
                 continue;
             }
-            
+
             $childCtMetadata = $ctMetadata->propertyMetadata[$childrenField];
             $children = $odmMetadata->getFieldValue($document, $childrenField);
 
@@ -112,7 +112,7 @@ public function prePersist(LifecycleEventArgs $args)
             $this->stack[] = [
                 'children' => $children,
                 'ct_metadata' => $childCtMetadata,
-                'field' => $childrenField
+                'field' => $childrenField,
             ];
         }
     }
diff --git a/tests/Functional/Container.php b/tests/Functional/Container.php
index 82ebe5c..f257afb 100644
--- a/tests/Functional/Container.php
+++ b/tests/Functional/Container.php
@@ -25,6 +25,7 @@
 use Psi\Component\ContentType\Form\Extension\FieldExtension;
 use Psi\Component\ContentType\Metadata\Driver\AnnotationDriver as CTAnnotationDriver;
 use Psi\Component\ContentType\Metadata\Driver\ArrayDriver;
+use Psi\Component\ContentType\Storage\Doctrine\PhpcrOdm\CollectionIdentifierUpdater;
 use Psi\Component\ContentType\Storage\Doctrine\PhpcrOdm\FieldMapper;
 use Psi\Component\ContentType\Storage\Doctrine\PhpcrOdm\NodeTypeRegistrator as CtNodeTypeRegistrator;
 use Psi\Component\ContentType\Storage\Doctrine\PhpcrOdm\PropertyEncoder;
@@ -44,7 +45,6 @@
 use Psi\Component\ContentType\View\ScalarView;
 use Psi\Component\ContentType\ViewRegistry;
 use Symfony\Component\Form\Forms;
-use Psi\Component\ContentType\Storage\Doctrine\PhpcrOdm\CollectionIdentifierUpdater;
 
 class Container extends PimpleContainer
 {
diff --git a/tests/Functional/Storage/Doctrine/PhpcrOdm/CollectionType/ObjectTest.php b/tests/Functional/Storage/Doctrine/PhpcrOdm/CollectionType/ObjectTest.php
index 7498519..3a82e9b 100644
--- a/tests/Functional/Storage/Doctrine/PhpcrOdm/CollectionType/ObjectTest.php
+++ b/tests/Functional/Storage/Doctrine/PhpcrOdm/CollectionType/ObjectTest.php
@@ -209,4 +209,3 @@ private function createArticleSlideshow()
         return $article;
     }
 }
-
diff --git a/tests/Functional/Storage/Doctrine/PhpcrOdm/CollectionType/ObjectUnrestrictTest.php b/tests/Functional/Storage/Doctrine/PhpcrOdm/CollectionType/ObjectUnrestrictTest.php
index 5cb3429..c3eca67 100644
--- a/tests/Functional/Storage/Doctrine/PhpcrOdm/CollectionType/ObjectUnrestrictTest.php
+++ b/tests/Functional/Storage/Doctrine/PhpcrOdm/CollectionType/ObjectUnrestrictTest.php
@@ -2,7 +2,6 @@
 
 namespace Psi\Component\ContentType\Tests\Functional\Storage\Doctrine\PhpcrOdm;
 
-use Doctrine\ODM\PHPCR\ChildrenCollection;
 use Psi\Component\ContentType\Tests\Functional\Example\Storage\Doctrine\PhpcrOdm\Article;
 use Psi\Component\ContentType\Tests\Functional\Example\Storage\Doctrine\PhpcrOdm\ArticleWithRestrictedChildren;
 use Psi\Component\ContentType\Tests\Functional\Example\Storage\Doctrine\PhpcrOdm\Image;
@@ -15,12 +14,13 @@ class ObjectUnrestrictTest extends PhpcrOdmTestCase
     public function init(array $mapping)
     {
         $container = $this->getContainer([
-            'mapping' => $mapping
+            'mapping' => $mapping,
         ]);
         $this->documentManager = $container->get('doctrine_phpcr.document_manager');
         $this->initPhpcr($this->documentManager);
         $this->updater = $container->get('psi_content_type.storage.doctrine.phpcr_odm.collection_updater');
     }
+
     /**
      * It should automatically allow mapped content objects as children.
      */
@@ -90,7 +90,7 @@ public function testCollectionAddToValidChildren()
         $article->id = '/test/article';
         $article->title = 'Foo';
         $article->date = new \DateTime();
-        $article->slideshow = [ $image1, $image2, $image3 ];
+        $article->slideshow = [$image1, $image2, $image3];
 
         $this->documentManager->persist($article);
         $this->updater->update($this->documentManager, $article);
@@ -100,7 +100,6 @@ public function testCollectionAddToValidChildren()
         $this->documentManager->find(null, '/test/article');
     }
 
-
     private function createArticleSlideshow()
     {
         $article = new Article();
@@ -119,4 +118,3 @@ private function createArticleSlideshow()
         return $article;
     }
 }
-
diff --git a/tests/Functional/Storage/Doctrine/PhpcrOdm/CollectionType/ScalarTest.php b/tests/Functional/Storage/Doctrine/PhpcrOdm/CollectionType/ScalarTest.php
index 3ec7493..c4f9142 100644
--- a/tests/Functional/Storage/Doctrine/PhpcrOdm/CollectionType/ScalarTest.php
+++ b/tests/Functional/Storage/Doctrine/PhpcrOdm/CollectionType/ScalarTest.php
@@ -2,10 +2,7 @@
 
 namespace Psi\Component\ContentType\Tests\Functional\Storage\Doctrine\PhpcrOdm;
 
-use Doctrine\ODM\PHPCR\ChildrenCollection;
 use Psi\Component\ContentType\Tests\Functional\Example\Storage\Doctrine\PhpcrOdm\Article;
-use Psi\Component\ContentType\Tests\Functional\Example\Storage\Doctrine\PhpcrOdm\ArticleWithRestrictedChildren;
-use Psi\Component\ContentType\Tests\Functional\Example\Storage\Doctrine\PhpcrOdm\Image;
 
 class ScalarTest extends PhpcrOdmTestCase
 {
@@ -66,4 +63,3 @@ public function testIntegerCollection()
         $this->assertSame([12, 13, 14], $article->numbers);
     }
 }
-
diff --git a/tests/Functional/Storage/Doctrine/PhpcrOdm/GeneralTest.php b/tests/Functional/Storage/Doctrine/PhpcrOdm/GeneralTest.php
index b8634f0..d93e2e8 100644
--- a/tests/Functional/Storage/Doctrine/PhpcrOdm/GeneralTest.php
+++ b/tests/Functional/Storage/Doctrine/PhpcrOdm/GeneralTest.php
@@ -2,9 +2,7 @@
 
 namespace Psi\Component\ContentType\Tests\Functional\Storage\Doctrine\PhpcrOdm;
 
-use Doctrine\ODM\PHPCR\ChildrenCollection;
 use Psi\Component\ContentType\Tests\Functional\Example\Storage\Doctrine\PhpcrOdm\Article;
-use Psi\Component\ContentType\Tests\Functional\Example\Storage\Doctrine\PhpcrOdm\ArticleWithRestrictedChildren;
 use Psi\Component\ContentType\Tests\Functional\Example\Storage\Doctrine\PhpcrOdm\Image;
 
 class GeneralTest extends PhpcrOdmTestCase
diff --git a/tests/Unit/Storage/Doctrine/PhpcrOdm/CollectionIdentifierUpdaterTest.php b/tests/Unit/Storage/Doctrine/PhpcrOdm/CollectionIdentifierUpdaterTest.php
index 62693bd..f344e8a 100644
--- a/tests/Unit/Storage/Doctrine/PhpcrOdm/CollectionIdentifierUpdaterTest.php
+++ b/tests/Unit/Storage/Doctrine/PhpcrOdm/CollectionIdentifierUpdaterTest.php
@@ -2,13 +2,13 @@
 
 namespace Psi\Component\ContentType\Tests\Unit\Storage\Doctrine\PhpcrOdm;
 
-use Metadata\MetadataFactoryInterface;
-use Psi\Component\ContentType\Storage\Doctrine\PhpcrOdm\PropertyEncoder;
-use Doctrine\ODM\PHPCR\Mapping\ClassMetadataFactory;
+use Doctrine\ODM\PHPCR\DocumentManagerInterface;
 use Doctrine\ODM\PHPCR\Mapping\ClassMetadata as OdmMetadata;
+use Doctrine\ODM\PHPCR\Mapping\ClassMetadataFactory;
+use Metadata\MetadataFactoryInterface;
 use Psi\Component\ContentType\Metadata\ClassMetadata;
 use Psi\Component\ContentType\Storage\Doctrine\PhpcrOdm\CollectionIdentifierUpdater;
-use Doctrine\ODM\PHPCR\DocumentManagerInterface;
+use Psi\Component\ContentType\Storage\Doctrine\PhpcrOdm\PropertyEncoder;
 
 class CollectionIdentifierUpdaterTest extends \PHPUnit_Framework_TestCase
 {
@@ -63,7 +63,7 @@ public function testIgnoreNonCtMappings()
 
         $this->odmMetadata->getIdentifierValue($this->document)->willReturn($identifier);
         $this->odmMetadata->childrenMappings = [
-            'some_collection'
+            'some_collection',
         ];
 
         $this->odmMetadata->getFieldValue($this->document, 'some_collection')->shouldNotBeCalled();
@@ -86,7 +86,7 @@ public function testSetIdentifierValue()
 
         $this->odmMetadata->getIdentifierValue($this->document)->willReturn($identifier);
         $this->odmMetadata->childrenMappings = [
-            'some_collection'
+            'some_collection',
         ];
         $this->ctMetadata->propertyMetadata = [
             'some_collection' => 'something',