diff --git a/src/Normalizer/ContentEntityNormalizer.php b/src/Normalizer/ContentEntityNormalizer.php
index 32bcd30..69da08b 100644
--- a/src/Normalizer/ContentEntityNormalizer.php
+++ b/src/Normalizer/ContentEntityNormalizer.php
@@ -5,6 +5,9 @@ namespace Drupal\value\Normalizer;
 use Drupal\Core\Entity\ContentEntityInterface;
 use Drupal\serialization\Normalizer\EntityNormalizer;
 
+/**
+ * Implements ContentEntityNormalizer class.
+ */
 class ContentEntityNormalizer extends EntityNormalizer {
 
   /**
@@ -26,4 +29,5 @@ class ContentEntityNormalizer extends EntityNormalizer {
 
     return $attributes;
   }
+
 }
diff --git a/src/Normalizer/EntityReferenceFieldItemNormalizer.php b/src/Normalizer/EntityReferenceFieldItemNormalizer.php
index 12b3f40..297db72 100644
--- a/src/Normalizer/EntityReferenceFieldItemNormalizer.php
+++ b/src/Normalizer/EntityReferenceFieldItemNormalizer.php
@@ -4,6 +4,9 @@ namespace Drupal\value\Normalizer;
 
 use Drupal\Core\Field\Plugin\Field\FieldType\EntityReferenceItem;
 
+/**
+ * Implements EntityReferenceFieldItemNormalizer class.
+ */
 class EntityReferenceFieldItemNormalizer extends NormalizerBase {
 
   /**
@@ -19,4 +22,5 @@ class EntityReferenceFieldItemNormalizer extends NormalizerBase {
     $attributes = $this->serializer->normalize($entity, $format, $context);
     return $attributes;
   }
+
 }
diff --git a/src/Normalizer/FieldItemListNormalizer.php b/src/Normalizer/FieldItemListNormalizer.php
index a482f35..9076d78 100644
--- a/src/Normalizer/FieldItemListNormalizer.php
+++ b/src/Normalizer/FieldItemListNormalizer.php
@@ -5,6 +5,9 @@ namespace Drupal\value\Normalizer;
 use Drupal\Core\Field\FieldConfigBase;
 use Drupal\Core\Field\FieldItemListInterface;
 
+/**
+ * Implements FieldItemListNormalizer class.
+ */
 class FieldItemListNormalizer extends NormalizerBase {
 
   /**
diff --git a/src/Normalizer/FieldItemNormalizer.php b/src/Normalizer/FieldItemNormalizer.php
index 2d5e2aa..f8c8ba2 100644
--- a/src/Normalizer/FieldItemNormalizer.php
+++ b/src/Normalizer/FieldItemNormalizer.php
@@ -5,6 +5,9 @@ namespace Drupal\value\Normalizer;
 use Drupal\Core\Field\FieldItemInterface;
 use Drupal\serialization\Normalizer\ComplexDataNormalizer;
 
+/**
+ * Impelements FieldItemNormalizer class.
+ */
 class FieldItemNormalizer extends ComplexDataNormalizer {
 
   /**
@@ -24,4 +27,5 @@ class FieldItemNormalizer extends ComplexDataNormalizer {
     $attributes = parent::normalize($object, $format, $context);
     return (count($attributes) == 1 && (isset($attributes['value']))) ? $attributes['value'] : $attributes;
   }
+
 }
diff --git a/src/Normalizer/FileFieldItemNormalizer.php b/src/Normalizer/FileFieldItemNormalizer.php
index 094ed59..a951163 100644
--- a/src/Normalizer/FileFieldItemNormalizer.php
+++ b/src/Normalizer/FileFieldItemNormalizer.php
@@ -5,6 +5,9 @@ namespace Drupal\value\Normalizer;
 use Drupal\file\FileInterface;
 use Drupal\file\Plugin\Field\FieldType\FileItem;
 
+/**
+ * Implements FileFieldItemNormalizer class.
+ */
 class FileFieldItemNormalizer extends FieldItemNormalizer {
 
   /**
@@ -26,4 +29,5 @@ class FileFieldItemNormalizer extends FieldItemNormalizer {
 
     return $attributes;
   }
+
 }
diff --git a/src/Normalizer/LinkFieldItemNormalizer.php b/src/Normalizer/LinkFieldItemNormalizer.php
index 4699ce4..4f528b7 100644
--- a/src/Normalizer/LinkFieldItemNormalizer.php
+++ b/src/Normalizer/LinkFieldItemNormalizer.php
@@ -5,6 +5,9 @@ namespace Drupal\value\Normalizer;
 use Drupal\Core\Url;
 use Drupal\link\LinkItemInterface;
 
+/**
+ * Implements LinkFieldItemNormalizer class.
+ */
 class LinkFieldItemNormalizer extends FieldItemNormalizer {
 
   /**
@@ -25,4 +28,5 @@ class LinkFieldItemNormalizer extends FieldItemNormalizer {
 
     return $attributes;
   }
+
 }
diff --git a/src/Normalizer/NormalizerBase.php b/src/Normalizer/NormalizerBase.php
index ea58cca..e2b241c 100644
--- a/src/Normalizer/NormalizerBase.php
+++ b/src/Normalizer/NormalizerBase.php
@@ -4,10 +4,14 @@ namespace Drupal\value\Normalizer;
 
 use Drupal\serialization\Normalizer\NormalizerBase as SerializationNormalizerBase;
 
+/**
+ * Implements NormalizerBase class.
+ */
 abstract class NormalizerBase extends SerializationNormalizerBase {
 
   /**
    * {@inheritdoc}
    */
   protected $format = 'value';
+
 }
diff --git a/src/ThemeManager.php b/src/ThemeManager.php
index 9774329..211e31d 100644
--- a/src/ThemeManager.php
+++ b/src/ThemeManager.php
@@ -12,6 +12,8 @@ class ThemeManager extends CoreThemeManager {
 
   /**
    * The variable prefix for Twig templates.
+   *
+   * @var string
    */
   public static $PREFIX = '_';
 
@@ -25,11 +27,6 @@ class ThemeManager extends CoreThemeManager {
 
   /**
    * Preprocesses variables for rendering.
-   *
-   * @param $hook
-   * @param $variables
-   *
-   * @return
    */
   protected function buildValues($hook, $variables) {
     // We want ContentEntity only for now.
@@ -43,11 +40,6 @@ class ThemeManager extends CoreThemeManager {
 
   /**
    * Finds the entity in context from the variables array.
-   *
-   * @param $hook
-   * @param $variables
-   *
-   * @return \Drupal\Core\Entity\ContentEntityInterface|null
    */
   protected function getEntity($hook, $variables) {
     if (is_string($hook)) {
@@ -61,6 +53,7 @@ class ThemeManager extends CoreThemeManager {
             $entity = $variables['content']["#block_content"];
           }
           break;
+
         default:
           if (isset($variables["#$hook"])) {
             $entity = $variables["#$hook"];
@@ -79,4 +72,5 @@ class ThemeManager extends CoreThemeManager {
 
     return NULL;
   }
+
 }
diff --git a/src/Twig/TwigExtension.php b/src/Twig/TwigExtension.php
index 535f775..ac2bf5e 100644
--- a/src/Twig/TwigExtension.php
+++ b/src/Twig/TwigExtension.php
@@ -5,14 +5,21 @@ namespace Drupal\value\Twig;
 use Drupal\Core\Entity\EntityTypeManagerInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 
+/**
+ * Implements TwigExtension class.
+ */
 class TwigExtension extends \Twig_Extension {
 
   /**
+   * Provides entity_type.manager service.
+   *
    * @var \Drupal\Core\Entity\EntityTypeManagerInterface
    */
   protected $entityTypeManager;
 
   /**
+   * Provides module_handler service.
+   *
    * @var \Drupal\Core\Extension\ModuleHandlerInterface
    */
   protected $moduleHandler;
@@ -21,7 +28,9 @@ class TwigExtension extends \Twig_Extension {
    * TwigExtension constructor.
    *
    * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
+   *   Provides an interface for entity type managers.
    * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
+   *   Interface for classes that manage a set of enabled modules.
    */
   public function __construct(EntityTypeManagerInterface $entity_type_manager, ModuleHandlerInterface $module_handler) {
     $this->entityTypeManager = $entity_type_manager;
@@ -36,10 +45,10 @@ class TwigExtension extends \Twig_Extension {
       // |markup.
       new \Twig_SimpleFilter('markup', [$this, 'markup']),
 
-      // |truncate
+      // |truncate.
       new \Twig_SimpleFilter('truncate', [$this, 'truncate']),
 
-      // |words
+      // |words.
       new \Twig_SimpleFilter('words', [$this, 'words']),
     ];
 
@@ -51,7 +60,7 @@ class TwigExtension extends \Twig_Extension {
     ]);
     $filters[] = new \Twig_SimpleFilter('where', [$this, 'arrayWhere']);
 
-    // |image_style
+    // |image_style.
     if ($this->moduleHandler->moduleExists('image')) {
       $filters[] = new \Twig_SimpleFilter('image_style', [$this, 'imageStyle']);
     }
@@ -61,15 +70,6 @@ class TwigExtension extends \Twig_Extension {
 
   /**
    * Returns safe markup for rendering HTML.
-   *
-   * @param string $text
-   *   The escaped text to render.
-   *
-   * @param null $format
-   *   The text format to use for processing.
-   *
-   * @return array
-   *   A renderable array.
    */
   public function markup($text, $format = NULL) {
     $value = $text;
@@ -94,12 +94,6 @@ class TwigExtension extends \Twig_Extension {
 
   /**
    * Truncates the number of characters in a string.
-   *
-   * @param $value
-   * @param int $length
-   * @param string $suffix
-   *
-   * @return string
    */
   public function truncate($string, $length = 100, $suffix = '...') {
     if (mb_strwidth($string, 'UTF-8') <= $length) {
@@ -111,12 +105,6 @@ class TwigExtension extends \Twig_Extension {
 
   /**
    * Truncates the number of words in a string.
-   *
-   * @param $string
-   * @param int $length
-   * @param string $suffix
-   *
-   * @return string
    */
   public function words($string, $length = 100, $suffix = '...') {
     preg_match('/^\s*+(?:\S++\s*+){1,' . $length . '}/u', $string, $matches);
@@ -130,16 +118,6 @@ class TwigExtension extends \Twig_Extension {
 
   /**
    * Returns the URL of an image in the image_style specified.
-   *
-   * @param $uri
-   *   The URI of the image.
-   * @param $image_style
-   *   The image style.
-   *
-   * @return null|string
-   *   The URL of the image with the style or NULL if not found.
-   *
-   * @throws \Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException
    */
   public function imageStyle($uri, $image_style) {
     $storage = $this->entityTypeManager->getStorage('image_style');
@@ -153,11 +131,6 @@ class TwigExtension extends \Twig_Extension {
 
   /**
    * Get a subset from an array based on a keys array.
-   *
-   * @param $array
-   * @param array|string $keys
-   *
-   * @return array
    */
   public function arrayPick($array, $keys) {
     if (!is_array($keys)) {
@@ -169,11 +142,6 @@ class TwigExtension extends \Twig_Extension {
 
   /**
    * Renames the keys in an array.
-   *
-   * @param $array
-   * @param $keys
-   *
-   * @return array
    */
   public function arrayRenameKeys($array, $keys) {
     if (is_array($array) && is_array($keys)) {
@@ -190,36 +158,39 @@ class TwigExtension extends \Twig_Extension {
 
   /**
    * Filters an array.
-   *
-   * @param $array
-   * @param $value
-   * @param string $operator
-   *
-   * @return array
    */
   public function arrayWhere($array, $value, $operator = '=') {
     return array_filter($array, function ($_value) use ($value, $operator) {
       switch ($operator) {
         case '=':
           return $_value == $value;
+
         case '!=':
           return $_value != $value;
+
         case '<':
           return $_value < $value;
+
         case '>':
           return $_value > $value;
+
         case '<=':
           return $_value <= $value;
+
         case '>=':
           return $_value >= $value;
+
         case '===':
           return $_value === $value;
+
         case '!==':
           return $_value !== $value;
+
         default:
       }
 
       return FALSE;
     });
   }
+
 }
diff --git a/src/ValueServiceProvider.php b/src/ValueServiceProvider.php
index aab89be..556ad72 100644
--- a/src/ValueServiceProvider.php
+++ b/src/ValueServiceProvider.php
@@ -5,6 +5,9 @@ namespace Drupal\value;
 use Drupal\Core\DependencyInjection\ContainerBuilder;
 use Drupal\Core\DependencyInjection\ServiceProviderBase;
 
+/**
+ * Implements ValueServiceProvider class.
+ */
 class ValueServiceProvider extends ServiceProviderBase {
 
   /**
diff --git a/value.module b/value.module
index 00c8fa2..b333f1d 100644
--- a/value.module
+++ b/value.module
@@ -1,6 +1,11 @@
 <?php
 
 /**
+ * @file
+ * Contains value.module.
+ */
+
+/**
  * Implements hook_preprocess().
  */
 function value_preprocess(&$variables) {
