diff --git a/swh/loader/mercurial/tasks.py b/swh/loader/mercurial/tasks.py
index 8162a3c..a4e5f6d 100644
--- a/swh/loader/mercurial/tasks.py
+++ b/swh/loader/mercurial/tasks.py
@@ -1,43 +1,43 @@
 # Copyright (C) 2017-2018  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 from swh.scheduler.task import Task
 
 from .bundle20_loader import HgBundle20Loader, HgArchiveBundle20Loader
 
 
 class LoadMercurialTsk(Task):
     """Mercurial repository loading
 
     """
     task_queue = 'swh_loader_mercurial'
 
-    def run_task(self, *, origin_url, visit_date, directory):
+    def run_task(self, *, origin_url, visit_date=None, directory=None):
         """Import a mercurial tarball into swh.
 
         Args: see :func:`DepositLoader.load`.
 
         """
         loader = HgBundle20Loader()
         loader.log = self.log
         return loader.load(origin_url=origin_url,
                            directory=directory,
                            visit_date=visit_date)
 
 
 class LoadArchiveMercurialTsk(Task):
     task_queue = 'swh_loader_mercurial_archive'
 
     def run_task(self, *, origin_url, archive_path, visit_date):
         """Import a mercurial tarball into swh.
 
         Args: see :func:`DepositLoader.load`.
 
         """
         loader = HgArchiveBundle20Loader()
         loader.log = self.log
         return loader.load(origin_url=origin_url,
                            archive_path=archive_path,
                            visit_date=visit_date)