diff --git a/main/inc/lib/api.lib.php b/main/inc/lib/api.lib.php
index aacb1c0462..c63cb350e0 100644
--- a/main/inc/lib/api.lib.php
+++ b/main/inc/lib/api.lib.php
@@ -9348,6 +9348,7 @@ function api_unserialize_content($type, $serialized, $ignoreErrors = false)
 {
     switch ($type) {
         case 'career':
+        case 'sequence_graph':
             $allowedClasses = [Graph::class, VerticesMap::class, Vertices::class, Edges::class];
             break;
         case 'lp':
diff --git a/src/Chamilo/CoreBundle/Entity/Sequence.php b/src/Chamilo/CoreBundle/Entity/Sequence.php
index 5fce1541fa..c576b8dbef 100644
--- a/src/Chamilo/CoreBundle/Entity/Sequence.php
+++ b/src/Chamilo/CoreBundle/Entity/Sequence.php
@@ -5,9 +5,6 @@ namespace Chamilo\CoreBundle\Entity;
 
 use Doctrine\ORM\Mapping as ORM;
 use Fhaculty\Graph\Graph;
-use Fhaculty\Graph\Set\Edges;
-use Fhaculty\Graph\Set\Vertices;
-use Fhaculty\Graph\Set\VerticesMap;
 use Gedmo\Mapping\Annotation as Gedmo;
 
 /**
@@ -138,17 +135,7 @@ class Sequence
      */
     public function getUnSerializeGraph()
     {
-        return Unserialize::unserialize(
-            $this->graph,
-            [
-                'allowed_classes' => [
-                    Graph::class,
-                    VerticesMap::class,
-                    Vertices::class,
-                    Edges::class,
-                ],
-            ]
-        );
+        return api_unserialize_content('sequence_graph', $this->graph);
     }
 
     /**
diff --git a/src/Chamilo/CourseBundle/Component/CourseCopy/Course.php b/src/Chamilo/CourseBundle/Component/CourseCopy/Course.php
index 108e65a3d8..7fee7505f0 100644
--- a/src/Chamilo/CourseBundle/Component/CourseCopy/Course.php
+++ b/src/Chamilo/CourseBundle/Component/CourseCopy/Course.php
@@ -3,34 +3,7 @@
 
 namespace Chamilo\CourseBundle\Component\CourseCopy;
 
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\Announcement;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\Attendance;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\CalendarEvent;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\CourseCopyLearnpath;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\CourseCopyTestCategory;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\CourseDescription;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\CourseSession;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\Document;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\Forum;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\ForumCategory;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\ForumPost;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\ForumTopic;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\Glossary;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\GradeBookBackup;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\Link;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\LinkCategory;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\Quiz;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\QuizQuestion;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\QuizQuestionOption;
 use Chamilo\CourseBundle\Component\CourseCopy\Resources\Resource;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\ScormDocument;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\Survey;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\SurveyInvitation;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\SurveyQuestion;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\Thematic;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\ToolIntro;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\Wiki;
-use Chamilo\CourseBundle\Component\CourseCopy\Resources\Work;
 
 /**
  * A course-object to use in Export/Import/Backup/Copy.
@@ -406,41 +379,9 @@ class Course
         if (extension_loaded('igbinary')) {
             $unserialized = igbinary_unserialize($course);
         } else {
-            $unserialized = Unserialize::unserialize(
-                $course,
-                [
-                    'allowed_classes' => [
-                        Course::class,
-                        Announcement::class,
-                        Attendance::class,
-                        CalendarEvent::class,
-                        CourseCopyLearnpath::class,
-                        CourseCopyTestCategory::class,
-                        CourseDescription::class,
-                        CourseSession::class,
-                        Document::class,
-                        Forum::class,
-                        ForumCategory::class,
-                        ForumPost::class,
-                        ForumTopic::class,
-                        Glossary::class,
-                        GradeBookBackup::class,
-                        Link::class,
-                        LinkCategory::class,
-                        Quiz::class,
-                        QuizQuestion::class,
-                        QuizQuestionOption::class,
-                        ScormDocument::class,
-                        Survey::class,
-                        SurveyInvitation::class,
-                        SurveyQuestion::class,
-                        Thematic::class,
-                        ToolIntro::class,
-                        Wiki::class,
-                        Work::class,
-                        \stdClass::class,
-                    ],
-                ]
+            $unserialized = api_unserialize_content(
+                'course',
+                $course
             );
         }