diff --git a/composer.json b/composer.json
index bdd502d..b8ac7fc 100644
--- a/composer.json
+++ b/composer.json
@@ -22,6 +22,7 @@
     "require": {
         "php": ">=7.1",
         "ext-dom": "*",
+        "ext-intl": "*",
         "masterminds/html5": "^2.4",
         "psr/log": "^1.0",
         "league/uri-parser": "^1.4.1"
diff --git a/src/SanitizerBuilder.php b/src/SanitizerBuilder.php
index ac05116..952bb77 100644
--- a/src/SanitizerBuilder.php
+++ b/src/SanitizerBuilder.php
@@ -42,16 +42,22 @@ class SanitizerBuilder implements SanitizerBuilderInterface
     public function registerExtension(ExtensionInterface $extension)
     {
         $this->extensions[$extension->getName()] = $extension;
+
+        return $this;
     }
 
     public function setParser(?ParserInterface $parser)
     {
         $this->parser = $parser;
+
+        return $this;
     }
 
     public function setLogger(?LoggerInterface $logger)
     {
         $this->logger = $logger;
+
+        return $this;
     }
 
     public function build(array $config): SanitizerInterface
diff --git a/src/SanitizerBuilderInterface.php b/src/SanitizerBuilderInterface.php
index 8e035f1..987bbe7 100644
--- a/src/SanitizerBuilderInterface.php
+++ b/src/SanitizerBuilderInterface.php
@@ -24,6 +24,8 @@ interface SanitizerBuilderInterface
      * Register an extension to use in the sanitizer being built.
      *
      * @param ExtensionInterface $extension
+     *
+     * @return SanitizerBuilderInterface
      */
     public function registerExtension(ExtensionInterface $extension);