diff --git a/swh/loader/core/converters.py b/swh/loader/core/converters.py
index 4a51ffb..a738ec2 100644
--- a/swh/loader/core/converters.py
+++ b/swh/loader/core/converters.py
@@ -1,76 +1,77 @@
 # Copyright (C) 2015-2020  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
 
 """Convert objects to dictionaries suitable for swh.storage"""
 
 import logging
 
 from typing import Dict, Iterable, List, Optional, Tuple
 
 from swh.model.hashutil import hash_to_hex
 from swh.model.model import BaseContent, Content, SkippedContent
 
 
 logger = logging.getLogger(__name__)
 
 
 def prepare_contents(
         contents: Iterable[Dict], max_content_size: Optional[int] = None,
         origin_url: Optional[str] = None) -> Tuple[
             List[Dict], List[Dict]]:
     """Prepare contents for storage from a list of contents
 
     Returns
         tuple of content iterable, skipped content iterable
 
     """
     present_contents: List[Dict] = []
     skipped_contents: List[Dict] = []
     for _content in contents:
         content = content_for_storage(
             _content, max_content_size=max_content_size, origin_url=origin_url)
         if isinstance(content, SkippedContent):
             skipped_contents.append(content.to_dict())
         else:
             present_contents.append(content.to_dict())
     return present_contents, skipped_contents
 
 
 def content_for_storage(
         content: Dict, max_content_size: Optional[int] = None,
         origin_url: Optional[str] = None) -> BaseContent:
     """Prepare content to be ready for storage
 
     Note:
     - 'data' is returned only if max_content_size is not reached.
 
     Returns:
         content with added data (or reason for being missing)
 
     """
     ret = content.copy()
     ret.pop('perms', None)
 
     if max_content_size and ret['length'] > max_content_size:
         logger.info('Skipping content %s, too large (%s > %s)' %
                     (hash_to_hex(content['sha1_git']),
                      ret['length'],
                      max_content_size))
         ret.pop('data', None)
         ret.update({'status': 'absent',
                     'reason': 'Content too large',
                     'origin': origin_url})
         return SkippedContent.from_dict(ret)
 
     if 'data' not in ret:
-        ret['data'] = open(ret['path'], 'rb').read()
+        with open(ret['path'], 'rb') as f:
+            ret['data'] = f.read()
 
     # Extra keys added by swh.model.from_disk, that are not accepted
     # by swh-storage
     ret.pop('path', None)
 
     ret['status'] = 'visible'
 
     return Content.from_dict(ret)