diff --git a/swh/lister/gitlab/tasks.py b/swh/lister/gitlab/tasks.py
--- a/swh/lister/gitlab/tasks.py
+++ b/swh/lister/gitlab/tasks.py
@@ -11,21 +11,21 @@
 from .lister import GitLabLister
 
 
-class GitLabListerTask(ListerTaskBase):
+class _GitLabListerTaskBase(ListerTaskBase):
     def new_lister(self, *, api_baseurl='https://gitlab.com/api/v4',
                    instance='gitlab', sort='asc', per_page=20):
         return GitLabLister(
             api_baseurl=api_baseurl, instance=instance, sort=sort)
 
 
-class RangeGitLabLister(GitLabListerTask, RangeListerTask):
+class RangeGitLabLister(_GitLabListerTaskBase, RangeListerTask):
     """Range GitLab lister (list available origins on specified range)
 
     """
     task_queue = 'swh_lister_gitlab_refresh'
 
 
-class FullGitLabRelister(GitLabListerTask):
+class FullGitLabRelister(_GitLabListerTaskBase):
     """Full GitLab lister (list all available origins from the api).
 
     """
@@ -46,7 +46,7 @@
               for minv, maxv in ranges)()
 
 
-class IncrementalGitLabLister(GitLabListerTask):
+class IncrementalGitLabLister(_GitLabListerTaskBase):
     """Incremental GitLab lister (list only new available origins).
 
     """