diff --git a/coder_sniffer/DrupalPractice/Project.php b/coder_sniffer/DrupalPractice/Project.php
index a2f3db5b..c7d6a6a5 100644
--- a/coder_sniffer/DrupalPractice/Project.php
+++ b/coder_sniffer/DrupalPractice/Project.php
@@ -190,7 +190,7 @@ public static function isServiceClass(File $phpcsFile, $classPtr)
             return false;
         }
 
-        $services = Yaml::parse(file_get_contents($ymlFile));
+        $services = Yaml::parse(file_get_contents($ymlFile), Yaml::PARSE_CUSTOM_TAGS);
         if (isset($services['services']) === false) {
             $cache[$phpcsFile->getFilename()] = false;
             return false;
diff --git a/tests/DrupalPractice/Objects/testmodule.services.yml b/tests/DrupalPractice/Objects/testmodule.services.yml
index 98f3a51e..b680731f 100644
--- a/tests/DrupalPractice/Objects/testmodule.services.yml
+++ b/tests/DrupalPractice/Objects/testmodule.services.yml
@@ -1,3 +1,8 @@
 services:
   testmodule.example:
     class: Drupal\testmodule\ExampleService
+
+  testmodule.test_tagged_iterator:
+    class: Drupal\testmodule\ExampleService
+    arguments:
+      - !tagged_iterator coder_test