diff --git a/core/lib/Drupal/Core/Template/Attribute.php b/core/lib/Drupal/Core/Template/Attribute.php
index c165981..c51e4d7 100644
--- a/core/lib/Drupal/Core/Template/Attribute.php
+++ b/core/lib/Drupal/Core/Template/Attribute.php
@@ -252,7 +252,7 @@ public function hasClass($class) {
    */
   public function __toString() {
     $keys = '';
-    $values = array();
+    $values = [];
     foreach ($this->storage as $name => $value) {
       $rendered = $value->render();
       if ($rendered) {
@@ -261,7 +261,7 @@ public function __toString() {
       }
     }
 
-    if(!$rendered){
+    if (!$rendered) {
       return '';
     }
     return SafeMarkup::format($keys, $values);
diff --git a/core/lib/Drupal/Core/Template/AttributeValueBase.php b/core/lib/Drupal/Core/Template/AttributeValueBase.php
index de87f7b..b1f0898 100644
--- a/core/lib/Drupal/Core/Template/AttributeValueBase.php
+++ b/core/lib/Drupal/Core/Template/AttributeValueBase.php
@@ -57,7 +57,7 @@ public function __construct($name, $value) {
   public function render() {
     $value = (string) $this;
     if (isset($this->value) && static::RENDER_EMPTY_ATTRIBUTE || !empty($value)) {
-      return SafeMarkup::format("@name = '@value'", ['@name' => $this->name, '@value' => $value]);
+      return SafeMarkup::format('@name="@value"', ['@name' => $this->name, '@value' => $value]);
     }
   }