diff --git a/core/lib/Drupal/Core/Template/TwigExtension.php b/core/lib/Drupal/Core/Template/TwigExtension.php
index 693da9a..702d4d2 100644
--- a/core/lib/Drupal/Core/Template/TwigExtension.php
+++ b/core/lib/Drupal/Core/Template/TwigExtension.php
@@ -156,18 +156,14 @@ public function getFilters() {
       // be used in "trans" tags.
       // @see TwigNodeTrans::compileString()
       new \Twig_SimpleFilter('placeholder', [$this, 'escapePlaceholder'], array('is_safe' => array('html'), 'needs_environment' => TRUE)),
-
       // Replace twig's escape filter with our own.
       new \Twig_SimpleFilter('drupal_escape', [$this, 'escapeFilter'], array('needs_environment' => true, 'is_safe_callback' => 'twig_escape_filter_is_safe')),
-
       // Implements safe joining.
       // @todo Make that the default for |join? Upstream issue:
       //   https://github.com/fabpot/Twig/issues/1420
       new \Twig_SimpleFilter('safe_join', [$this, 'safeJoin'], ['needs_environment' => true, 'is_safe' => ['html']]),
-
       // Array filters.
       new \Twig_SimpleFilter('without', 'twig_without'),
-
       // CSS class and ID filters.
       new \Twig_SimpleFilter('clean_class', '\Drupal\Component\Utility\Html::getClass'),
       new \Twig_SimpleFilter('clean_id', '\Drupal\Component\Utility\Html::getId'),
@@ -372,6 +368,9 @@ public function attachLibrary($library) {
    *
    * @return string|null
    *   The escaped, rendered output, or NULL if there is no valid output.
+   *
+   * @throws \Exception
+   *   When passed $string as an object that has no __toString() method.
    */
   public function escapePlaceholder($env, $string) {
     return '<em class="placeholder">' . $this->escapeFilter($env, $string) . '</em>';
@@ -400,6 +399,9 @@ public function escapePlaceholder($env, $string) {
    * @return string|null
    *   The escaped, rendered output, or NULL if there is no valid output.
    *
+   * @throws \Exception
+   *   When passed $arg is an object that has no __toString() method.
+   *
    * @todo Refactor this to keep it in sync with theme_render_and_autoescape()
    *   in https://www.drupal.org/node/2575065
    */
@@ -431,7 +433,7 @@ public function escapeFilter(\Twig_Environment $env, $arg, $strategy = 'html', $
       elseif (method_exists($arg, '__toString')) {
         $return = (string) $arg;
       }
-      // You can't throw exceptions in the magic PHP __toString methods, see
+      // You can't throw exceptions in the magic PHP __toString() methods, see
       // http://php.net/manual/en/language.oop5.magic.php#object.tostring so
       // we also support a toString method.
       elseif (method_exists($arg, 'toString')) {
@@ -457,7 +459,6 @@ public function escapeFilter(\Twig_Environment $env, $arg, $strategy = 'html', $
 
     // This is a normal render array, which is safe by definition, with
     // special simple cases already handled.
-
     // Early return if this element was pre-rendered (no need to re-render).
     if (isset($arg['#printed']) && $arg['#printed'] == TRUE && isset($arg['#markup']) && strlen($arg['#markup']) > 0) {
       return $arg['#markup'];
@@ -469,11 +470,10 @@ public function escapeFilter(\Twig_Environment $env, $arg, $strategy = 'html', $
   /**
    * Wrapper around render() for twig printed output.
    *
-   * If an object is passed that has no __toString method an exception is thrown;
-   * other objects are casted to string. However in the case that the object is an
-   * instance of a Twig_Markup object it is returned directly to support auto
-   * escaping.
-   *
+   * If an object is passed that has no __toString() method an exception is
+   * thrown; Other objects are casted to string. However in the case that the
+   * object is an instance of a Twig_Markup object it is returned directly to
+   * support auto escaping.
    * If an array is passed it is rendered via render() and scalar values are
    * returned directly.
    *
@@ -483,6 +483,9 @@ public function escapeFilter(\Twig_Environment $env, $arg, $strategy = 'html', $
    * @return mixed
    *   The rendered output or an Twig_Markup object.
    *
+   * @throws \Exception
+   *   When passed $arg as an object that has no __toString() method.
+   *
    * @see render
    * @see TwigNodeVisitor
    */
@@ -509,7 +512,7 @@ public function renderVar($arg) {
       elseif (method_exists($arg, '__toString')) {
         return (string) $arg;
       }
-      // You can't throw exceptions in the magic PHP __toString methods, see
+      // You can't throw exceptions in the magic PHP __toString() methods, see
       // http://php.net/manual/en/language.oop5.magic.php#object.tostring so
       // we also support a toString method.
       elseif (method_exists($arg, 'toString')) {
@@ -550,9 +553,9 @@ public function safeJoin(\Twig_Environment $env, $value, $glue = '') {
     }
 
     return implode($glue, array_map(function($item) use ($env) {
-      // If $item is not marked safe then it will be escaped.
-      return $this->escapeFilter($env, $item, 'html', NULL, TRUE);
-    }, (array) $value));
+          // If $item is not marked safe then it will be escaped.
+          return $this->escapeFilter($env, $item, 'html', NULL, TRUE);
+        }, (array) $value));
   }
 
 }
diff --git a/core/modules/contextual/src/ContextualController.php b/core/modules/contextual/src/ContextualController.php
index 62ee55a..a0afafa 100644
--- a/core/modules/contextual/src/ContextualController.php
+++ b/core/modules/contextual/src/ContextualController.php
@@ -30,6 +30,9 @@ class ContextualController implements ContainerAwareInterface {
    *
    * @return \Symfony\Component\HttpFoundation\JsonResponse
    *   The JSON response.
+   *
+   * @throws \Symfony\Component\HttpKernel\Exception\BadRequestHttpException
+   *   Thrown when the contextual IDs are not found.
    */
   public function render(Request $request) {
     $ids = $request->request->get('ids');
diff --git a/core/modules/editor/src/EditorController.php b/core/modules/editor/src/EditorController.php
index fd605cd..f491e23 100644
--- a/core/modules/editor/src/EditorController.php
+++ b/core/modules/editor/src/EditorController.php
@@ -60,6 +60,9 @@ public function getUntransformedText(EntityInterface $entity, $field_name, $lang
    * @return \Symfony\Component\HttpFoundation\JsonResponse
    *   A JSON response containing the XSS-filtered value.
    *
+   * @throws \Symfony\Component\HttpKernel\Exception\NotFoundHttpException
+   *   Thrown when there is no value found with requested object to filter.
+   *
    * @see editor_filter_xss()
    */
   public function filterXss(Request $request, FilterFormatInterface $filter_format) {
diff --git a/core/modules/field/field.api.php b/core/modules/field/field.api.php
index fb85d62..2b3ecd7 100644
--- a/core/modules/field/field.api.php
+++ b/core/modules/field/field.api.php
@@ -71,6 +71,9 @@ function hook_field_info_alter(&$info) {
  * @param \Drupal\field\FieldStorageConfigInterface $prior_field_storage
  *   The field storage as it is pre-update.
  *
+ * @throws \Drupal\Core\Entity\Exception\FieldStorageDefinitionUpdateForbiddenException
+ * Thrown when a storage definition update is forbidden.
+ *
  * @see entity_crud
  */
 function hook_field_storage_config_update_forbid(\Drupal\field\FieldStorageConfigInterface $field_storage, \Drupal\field\FieldStorageConfigInterface $prior_field_storage) {
diff --git a/core/modules/field/field.purge.inc b/core/modules/field/field.purge.inc
index bd9203c..b7efaee 100644
--- a/core/modules/field/field.purge.inc
+++ b/core/modules/field/field.purge.inc
@@ -156,7 +156,8 @@ function field_purge_field(FieldConfigInterface $field) {
  * @param \Drupal\field\FieldStorageConfigInterface $field_storage
  *   The field storage to purge.
  *
- * @throws Drupal\field\FieldException
+ * @throws \Drupal\Core\Field\FieldException
+ *   Thrown when the field storage has fields.
  */
 function field_purge_field_storage(FieldStorageConfigInterface $field_storage) {
   $fields = entity_load_multiple_by_properties('field_config', array('field_storage_uuid' => $field_storage->uuid(), 'include_deleted' => TRUE));
diff --git a/core/modules/field/src/Entity/FieldConfig.php b/core/modules/field/src/Entity/FieldConfig.php
index 8e0e0b4..2d25641 100644
--- a/core/modules/field/src/Entity/FieldConfig.php
+++ b/core/modules/field/src/Entity/FieldConfig.php
@@ -88,6 +88,11 @@ class FieldConfig extends FieldConfigBase implements FieldConfigInterface {
    *   used to set the corresponding properties on the class; see the class
    *   property documentation for details.
    *
+   * @throws \Drupal\Core\Field\FieldException
+   *   Thrown when the given field storage is not an instance of
+   *   FieldStorageConfigInterface and also thrown if there is no field name,
+   *   entity type, or bundle associated.
+   *
    * @see entity_create()
    */
   public function __construct(array $values, $entity_type = 'field_config') {
diff --git a/core/modules/field/src/Entity/FieldStorageConfig.php b/core/modules/field/src/Entity/FieldStorageConfig.php
index d4c2922..81bf66f 100644
--- a/core/modules/field/src/Entity/FieldStorageConfig.php
+++ b/core/modules/field/src/Entity/FieldStorageConfig.php
@@ -241,6 +241,11 @@ class FieldStorageConfig extends ConfigEntityBase implements FieldStorageConfigI
    * entity_create('field_storage_config', $values)), where $values is the same
    * parameter as in this constructor.
    *
+   * @throws \Drupal\Core\Field\FieldException
+   *   Thrown when there is no field name, there are special characters found in
+   *   field name, there is no field type specified, or there is no entity type
+   *   associated.
+   *
    * @see entity_create()
    */
   public function __construct(array $values, $entity_type = 'field_storage_config') {
diff --git a/core/modules/hal/src/Normalizer/ContentEntityNormalizer.php b/core/modules/hal/src/Normalizer/ContentEntityNormalizer.php
index 9c71da4..e628f3b 100644
--- a/core/modules/hal/src/Normalizer/ContentEntityNormalizer.php
+++ b/core/modules/hal/src/Normalizer/ContentEntityNormalizer.php
@@ -125,6 +125,7 @@ public function normalize($entity, $format = NULL, array $context = array()) {
    *     entity.
    *
    * @throws \Symfony\Component\Serializer\Exception\UnexpectedValueException
+   *   Thrown when there is no type link relation specified.
    */
   public function denormalize($data, $class, $format = NULL, array $context = array()) {
     // Get type, necessary for determining which bundle to create.
@@ -222,6 +223,8 @@ protected function getEntityUri(EntityInterface $entity) {
    * @return array
    *   The typed data IDs.
    *
+   * @throws \Symfony\Component\Serializer\Exception\UnexpectedValueException
+   *   Thrown when there is no link type attribute found.
    */
   protected function getTypedDataIds($types, $context = array()) {
     // The 'type' can potentially contain an array of type objects. By default,
diff --git a/core/modules/history/src/Controller/HistoryController.php b/core/modules/history/src/Controller/HistoryController.php
index 9d6c394..1441218 100644
--- a/core/modules/history/src/Controller/HistoryController.php
+++ b/core/modules/history/src/Controller/HistoryController.php
@@ -25,6 +25,11 @@ class HistoryController extends ControllerBase {
    * @param \Symfony\Component\HttpFoundation\Request $request
    *   The request of the page.
    *
+   * @throws \Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException
+   * AccessDeniedHttpException represents an "Access Denined for unauthorised user"
+   * @throws \Symfony\Component\HttpKernel\Exception\NotFoundHttpException
+   * NotFoundHttpException represents a "Page Not found"
+   *
    * @return Symfony\Component\HttpFoundation\JsonResponse
    *   The JSON response.
    */
@@ -45,8 +50,13 @@ public function getNodeReadTimestamps(Request $request) {
    *
    * @param \Symfony\Component\HttpFoundation\Request $request
    *   The request of the page.
+   *
    * @param \Drupal\node\NodeInterface $node
    *   The node whose "last read" timestamp should be updated.
+   *
+   * @throws \Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException
+   * AccessDeniedHttpException represents an "Access Denined for unauthorised 
+   * user"
    */
   public function readNode(Request $request, NodeInterface $node) {
     if ($this->currentUser()->isAnonymous()) {
diff --git a/core/modules/language/src/Entity/ContentLanguageSettings.php b/core/modules/language/src/Entity/ContentLanguageSettings.php
index 7501012..aca58fa 100644
--- a/core/modules/language/src/Entity/ContentLanguageSettings.php
+++ b/core/modules/language/src/Entity/ContentLanguageSettings.php
@@ -77,6 +77,9 @@ class ContentLanguageSettings extends ConfigEntityBase implements ContentLanguag
    *   Other array elements will be used to set the corresponding properties on
    *   the class; see the class property documentation for details.
    *
+   * @throws \Drupal\language\ContentLanguageSettingsException
+   *   Thrown when there is no entity type or bundle associated.
+   *
    * @see entity_create()
    */
   public function __construct(array $values, $entity_type = 'language_content_settings') {
diff --git a/core/modules/locale/src/Gettext.php b/core/modules/locale/src/Gettext.php
index 4d5b65e..7cff4de 100644
--- a/core/modules/locale/src/Gettext.php
+++ b/core/modules/locale/src/Gettext.php
@@ -42,6 +42,9 @@ class Gettext {
    * @return array
    *   Report array as defined in Drupal\locale\PoDatabaseWriter.
    *
+   * @throws \Exception
+   *   Thrown when there is no header found.
+   *
    * @see \Drupal\locale\PoDatabaseWriter
    */
   public static function fileToDatabase($file, $options) {
diff --git a/core/modules/locale/src/PoDatabaseWriter.php b/core/modules/locale/src/PoDatabaseWriter.php
index 1ee862a..37ec913 100644
--- a/core/modules/locale/src/PoDatabaseWriter.php
+++ b/core/modules/locale/src/PoDatabaseWriter.php
@@ -149,7 +149,9 @@ public function getHeader() {
    * @param \Drupal\Component\Gettext\PoHeader $header
    *   Header metadata.
    *
-   * @throws Exception
+   * @throws \Exception
+   *   Thrown when the options already exist, or the language code is not
+   *   assigned.
    */
   public function setHeader(PoHeader $header) {
     $this->header = $header;
diff --git a/core/modules/quickedit/src/QuickEditController.php b/core/modules/quickedit/src/QuickEditController.php
index ed26a09..08010c4 100644
--- a/core/modules/quickedit/src/QuickEditController.php
+++ b/core/modules/quickedit/src/QuickEditController.php
@@ -95,6 +95,9 @@ public static function create(ContainerInterface $container) {
    *
    * @return \Symfony\Component\HttpFoundation\JsonResponse
    *   The JSON response.
+   *
+   * @throws \Symfony\Component\HttpKernel\Exception\NotFoundHttpException
+   * NotFoundHttpException represents a "Page Not found"
    */
   public function metadata(Request $request) {
     $fields = $request->request->get('fields');
@@ -146,6 +149,9 @@ public function metadata(Request $request) {
    *
    * @return \Drupal\Core\Ajax\AjaxResponse
    *   The Ajax response.
+   *
+   * @throws \Symfony\Component\HttpKernel\Exception\NotFoundHttpException
+   * NotFoundHttpException represents a "Page Not found"
    */
   public function attachments(Request $request) {
     $response = new AjaxResponse();
diff --git a/core/modules/responsive_image/responsive_image.module b/core/modules/responsive_image/responsive_image.module
index af87c5b..684bf13 100644
--- a/core/modules/responsive_image/responsive_image.module
+++ b/core/modules/responsive_image/responsive_image.module
@@ -360,6 +360,9 @@ function template_preprocess_responsive_image(&$variables) {
  *
  * @return \Drupal\Core\Template\Attribute[]
  *   An array of attributes for the source tag.
+ *
+ * @throws \LogicException
+ *   Thrown when the image's width is not specified.
  */
 function responsive_image_build_source_attributes(ImageInterface $image, array $variables, BreakpointInterface $breakpoint, array $multipliers) {
   $width = isset($variables['width']) && !empty($variables['width']) ? $variables['width'] : $image->getWidth();
diff --git a/core/modules/rest/src/RequestHandler.php b/core/modules/rest/src/RequestHandler.php
index 5a04cd8..47d86e3 100644
--- a/core/modules/rest/src/RequestHandler.php
+++ b/core/modules/rest/src/RequestHandler.php
@@ -34,6 +34,9 @@ class RequestHandler implements ContainerAwareInterface {
    *
    * @return \Symfony\Component\HttpFoundation\Response
    *   The response object.
+   *
+   * @throws \Symfony\Component\HttpKernel\Exception\UnsupportedMediaTypeHttpException
+   * UnsupportedMediaTypeHttpException represents an "Unsupported Media Type"
    */
   public function handle(RouteMatchInterface $route_match, Request $request) {
 
diff --git a/core/modules/simpletest/src/WebTestBase.php b/core/modules/simpletest/src/WebTestBase.php
index 2edfc81..e3032aa 100644
--- a/core/modules/simpletest/src/WebTestBase.php
+++ b/core/modules/simpletest/src/WebTestBase.php
@@ -1255,6 +1255,9 @@ protected function tearDown() {
    * add HTTP authentication headers. This is necessary for testing sites that
    * are protected by login credentials from public access.
    * See the description of $curl_options for other options.
+   *
+   * @throws \UnexpectedValueException
+   *   Thrown when the specified cURL options have already been set.
    */
   protected function curlInitialize() {
     global $base_url;
@@ -1703,6 +1706,9 @@ protected function drupalGetXHR($path, array $options = array(), array $headers
    *   is done by drupalPostAjaxForm(). This string is literally appended to the
    *   POST data, so it must already be urlencoded and contain a leading "&"
    *   (e.g., "&extra_var1=hello+world&extra_var2=you%26me").
+   *
+   * @throws \Exception
+   *   Thrown when there is no Ajax path specified.
    */
   protected function drupalPostForm($path, $edit, $submit, array $options = array(), array $headers = array(), $form_html_id = NULL, $extra_post = NULL) {
     if (is_object($submit)) {
@@ -1846,6 +1852,9 @@ protected function drupalPostForm($path, $edit, $submit, array $options = array(
    * @return
    *   An array of Ajax commands.
    *
+   * @throws \Exception
+   *   Thrown when there is no Ajax path specified.
+   *
    * @see drupalPostForm()
    * @see drupalProcessAjaxResponse()
    * @see ajax.js
diff --git a/core/modules/system/src/Plugin/ImageToolkit/GDToolkit.php b/core/modules/system/src/Plugin/ImageToolkit/GDToolkit.php
index f9cfb53..e7520d4 100644
--- a/core/modules/system/src/Plugin/ImageToolkit/GDToolkit.php
+++ b/core/modules/system/src/Plugin/ImageToolkit/GDToolkit.php
@@ -121,6 +121,9 @@ public static function create(ContainerInterface $container, array $configuratio
    *
    * @return \Drupal\system\Plugin\ImageToolkit\GDToolkit
    *   An instance of the current toolkit object.
+   *
+   * @throws \InvalidArgumentException
+   *   Thrown when the given image resource is not valid.
    */
   public function setResource($resource) {
     if (!is_resource($resource) || get_resource_type($resource) != 'gd') {
diff --git a/core/modules/system/src/Tests/Routing/MockAliasManager.php b/core/modules/system/src/Tests/Routing/MockAliasManager.php
index 55f2ae2..2c8c4b5 100644
--- a/core/modules/system/src/Tests/Routing/MockAliasManager.php
+++ b/core/modules/system/src/Tests/Routing/MockAliasManager.php
@@ -51,6 +51,9 @@ class MockAliasManager implements AliasManagerInterface {
    *   The alias of the system path.
    * @param type $path_language
    *   The language of this alias.
+   *
+   * @throws \InvalidArgumentException
+   *   Thrown when the path or alias does not begin with a slash.
    */
   public function addAlias($path, $alias, $path_language = NULL) {
     $language = $path_language ?: $this->defaultLanguage;
diff --git a/core/modules/user/src/Controller/UserController.php b/core/modules/user/src/Controller/UserController.php
index 772884b..c991850 100644
--- a/core/modules/user/src/Controller/UserController.php
+++ b/core/modules/user/src/Controller/UserController.php
@@ -189,6 +189,10 @@ public function logout() {
    *
    * @return \Symfony\Component\HttpFoundation\RedirectResponse
    *   A redirect response.
+   *
+   * @throws \Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException
+   * AccessDeniedHttpException represents an "Access Denined for unauthorised 
+   * user"
    */
   public function confirmCancel(UserInterface $user, $timestamp = 0, $hashed_pass = '') {
     // Time out in seconds until cancel URL expires; 24 hours = 86400 seconds.
diff --git a/core/modules/user/src/PrivateTempStore.php b/core/modules/user/src/PrivateTempStore.php
index 3b5fe4a..677b873 100644
--- a/core/modules/user/src/PrivateTempStore.php
+++ b/core/modules/user/src/PrivateTempStore.php
@@ -115,6 +115,9 @@ public function get($key) {
    *   The key of the data to store.
    * @param mixed $value
    *   The data to store.
+   *
+   * @throws \Drupal\user\TempStoreException
+   *   Thrown when a lock cannot be acquired.
    */
   public function set($key, $value) {
     $key = $this->createkey($key);
@@ -164,6 +167,9 @@ public function getMetadata($key) {
    * @return bool
    *   TRUE if the object was deleted or does not exist, FALSE if it exists but
    *   is not owned by $this->owner.
+   *
+   * @throws \Drupal\user\TempStoreException
+   *   Thrown when a lock cannot be acquired.
    */
   public function delete($key) {
     $key = $this->createkey($key);
diff --git a/core/modules/user/src/SharedTempStore.php b/core/modules/user/src/SharedTempStore.php
index 0a70b7f..501ed8c 100644
--- a/core/modules/user/src/SharedTempStore.php
+++ b/core/modules/user/src/SharedTempStore.php
@@ -190,6 +190,9 @@ public function setIfOwner($key, $value) {
    *   The key of the data to store.
    * @param mixed $value
    *   The data to store.
+   *
+   * @throws \Drupal\user\TempStoreException
+   *   Thrown when a lock cannot be acquired.
    */
   public function set($key, $value) {
     if (!$this->lockBackend->acquire($key)) {
@@ -233,6 +236,9 @@ public function getMetadata($key) {
    *
    * @param string $key
    *   The key of the data to delete.
+   *
+   * @throws \Drupal\user\TempStoreException
+   *   Thrown when a lock cannot be acquired.
    */
   public function delete($key) {
     if (!$this->lockBackend->acquire($key)) {
diff --git a/core/modules/views/src/Controller/ViewAjaxController.php b/core/modules/views/src/Controller/ViewAjaxController.php
index bd2f3c1..897f456 100644
--- a/core/modules/views/src/Controller/ViewAjaxController.php
+++ b/core/modules/views/src/Controller/ViewAjaxController.php
@@ -111,6 +111,8 @@ public static function create(ContainerInterface $container) {
    *
    * @throws \Symfony\Component\HttpKernel\Exception\NotFoundHttpException
    *   Thrown when the view was not found.
+   * @throws \Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException
+   *   Thrown if either the view isn't found, or the access check fails.
    */
   public function ajaxView(Request $request) {
     $name = $request->request->get('view_name');
diff --git a/core/modules/views/src/ViewExecutable.php b/core/modules/views/src/ViewExecutable.php
index 9f5d32a..0c28b20 100644
--- a/core/modules/views/src/ViewExecutable.php
+++ b/core/modules/views/src/ViewExecutable.php
@@ -1781,6 +1781,11 @@ public function hasUrl($args = NULL, $display_id = NULL) {
    *   (optional) Specify the display ID to link to, fallback to the current ID.
    *
    * @return \Drupal\Core\Url
+   *   The display URL object.
+   *
+   * @throws \InvalidArgumentException
+   *   Thrown when the display plugin does not have a URL to return.
+   *
    */
   public function getUrl($args = NULL, $display_id = NULL) {
     if (!empty($this->override_url)) {
diff --git a/core/modules/views/src/Views.php b/core/modules/views/src/Views.php
index 06b835e..6811af1 100644
--- a/core/modules/views/src/Views.php
+++ b/core/modules/views/src/Views.php
@@ -507,6 +507,9 @@ public static function getHandlerTypes() {
    *
    * @return array
    *   An array of plugin types.
+   *
+   * @throws \Exception
+   *   Thrown when the type is neither plugin nor handler.
    */
   public static function getPluginTypes($type = NULL) {
     if ($type === NULL) {