diff --git a/src/Helpers/ExtensionHelper.php b/src/Helpers/ExtensionHelper.php
deleted file mode 100644
index f6a756b..0000000
--- a/src/Helpers/ExtensionHelper.php
+++ /dev/null
@@ -1,62 +0,0 @@
-<?php
-
-namespace Chrometoaster\AdvancedTaxonomies\Helpers;
-
-use SilverStripe\Core\ClassInfo;
-use SilverStripe\Core\Extensible;
-use SilverStripe\Dev\TestOnly;
-
-class ExtensionHelper
-{
-    use Extensible;
-
-
-    public static function classes_being_applied(
-        $baseClass,
-        $extensionName,
-        $includeBaseClass = false,
-        $includeSubClass = false,
-        $excludeTestOnly = true
-    ) {
-        $doClasses = ClassInfo::subclassesFor($baseClass, $includeBaseClass);
-        $excluded  = [];
-
-        foreach ($doClasses as $doClassKey => $doClassName) {
-            if (array_key_exists($doClassKey, $excluded)) {
-                continue;
-            }
-
-            if ($excludeTestOnly) {
-                if (is_a($doClassName, TestOnly::class, true)) {
-                    unset($doClasses[$doClassKey]);
-                    $excluded[$doClassKey] = $doClassName;
-                    if (!$includeSubClass) {
-                        foreach (ClassInfo::subclassesFor($doClassName, false) as $subClassKey => $subClassName) {
-                            if (isset($doClasses[$subClassKey])) {
-                                unset($doClasses[$subClassName]);
-                                $excluded[$subClassKey] = $subClassName;
-                            }
-                        }
-                    }
-
-                    continue;
-                }
-            }
-
-            if (!self::has_extension($doClassName, $extensionName)) {
-                unset($doClasses[$doClassKey]);
-            } else { //has applied the extension
-                if (!$includeSubClass) {
-                    foreach (ClassInfo::subclassesFor($doClassName, false) as $subClassKey => $subClassName) {
-                        if (isset($doClasses[$subClassKey])) {
-                            unset($doClasses[$subClassKey]);
-                            $excluded[$subClassKey] = $subClassName;
-                        }
-                    }
-                }
-            }
-        }
-
-        return $doClasses;
-    }
-}