We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Fulah locale exposes _XXX_LAST_SUBMISSION_
When in the Fulah (ff) locale, all pages expose the `_XXX_LAST_SUBMISSION_` text used to mangle timesince messages.

![screen shot 2017-05-11 at 19 58 59](https://cloud.githubusercontent.com/assets/647438/25966915/58d16d2e-3684-11e7-9eac-28fbe147a7ab.png)


--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `pootle/i18n/dates.py`
Content:
```
1 # -*- coding: utf-8 -*-
2 #
3 # Copyright (C) Pootle contributors.
4 #
5 # This file is a part of the Pootle project. It is distributed under the GPL3
6 # or later license. See the LICENSE file for a copy of the license and the
7 # AUTHORS file for copyright and authorship information.
8 
9 from datetime import datetime
10 
11 
12 from .formatter import get_locale_formats
13 
14 
15 def timesince(timestamp, locale=None):
16     timedelta = datetime.now() - datetime.fromtimestamp(timestamp)
17     return get_locale_formats(locale).timedelta(timedelta, format='long')
18
```
--- END FILES ---

Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.

Here is an example:

```diff
diff --git a/examples/server_async.py b/examples/server_async.py
--- a/examples/server_async.py
+++ b/examples/server_async.py
@@ -313,4 +313,4 @@
 
 
 if __name__ == "__main__":
-    asyncio.run(run_async_server("."), debug=True)
+    asyncio.run(run_async_server(), debug=True)
diff --git a/examples/server_sync.py b/examples/server_sync.py
--- a/examples/server_sync.py
+++ b/examples/server_sync.py
@@ -313,5 +313,5 @@
 
 
 if __name__ == "__main__":
-    server = run_sync_server(".")
+    server = run_sync_server()
     server.shutdown()

```

diff --git a/pootle/i18n/dates.py b/pootle/i18n/dates.py
--- a/pootle/i18n/dates.py
+++ b/pootle/i18n/dates.py
@@ -8,10 +8,15 @@
 
 from datetime import datetime
 
+from django.conf import settings
 
 from .formatter import get_locale_formats
 
 
 def timesince(timestamp, locale=None):
     timedelta = datetime.now() - datetime.fromtimestamp(timestamp)
-    return get_locale_formats(locale).timedelta(timedelta, format='long')
+    formatted = get_locale_formats(locale).timedelta(timedelta, format='long')
+    if formatted:
+        return formatted
+    return get_locale_formats(
+        settings.LANGUAGE_CODE).timedelta(timedelta, format='long')

{"golden_diff": "diff --git a/pootle/i18n/dates.py b/pootle/i18n/dates.py\n--- a/pootle/i18n/dates.py\n+++ b/pootle/i18n/dates.py\n@@ -8,10 +8,15 @@\n \n from datetime import datetime\n \n+from django.conf import settings\n \n from .formatter import get_locale_formats\n \n \n def timesince(timestamp, locale=None):\n     timedelta = datetime.now() - datetime.fromtimestamp(timestamp)\n-    return get_locale_formats(locale).timedelta(timedelta, format='long')\n+    formatted = get_locale_formats(locale).timedelta(timedelta, format='long')\n+    if formatted:\n+        return formatted\n+    return get_locale_formats(\n+        settings.LANGUAGE_CODE).timedelta(timedelta, format='long')\n", "issue": "Fulah locale exposes _XXX_LAST_SUBMISSION_\nWhen in the Fulah (ff) locale, all pages expose the `_XXX_LAST_SUBMISSION_` text used to mangle timesince messages.\r\n\r\n![screen shot 2017-05-11 at 19 58 59](https://cloud.githubusercontent.com/assets/647438/25966915/58d16d2e-3684-11e7-9eac-28fbe147a7ab.png)\r\n\n", "before_files": [{"content": "# -*- coding: utf-8 -*-\n#\n# Copyright (C) Pootle contributors.\n#\n# This file is a part of the Pootle project. It is distributed under the GPL3\n# or later license. See the LICENSE file for a copy of the license and the\n# AUTHORS file for copyright and authorship information.\n\nfrom datetime import datetime\n\n\nfrom .formatter import get_locale_formats\n\n\ndef timesince(timestamp, locale=None):\n    timedelta = datetime.now() - datetime.fromtimestamp(timestamp)\n    return get_locale_formats(locale).timedelta(timedelta, format='long')\n", "path": "pootle/i18n/dates.py"}], "after_files": [{"content": "# -*- coding: utf-8 -*-\n#\n# Copyright (C) Pootle contributors.\n#\n# This file is a part of the Pootle project. It is distributed under the GPL3\n# or later license. See the LICENSE file for a copy of the license and the\n# AUTHORS file for copyright and authorship information.\n\nfrom datetime import datetime\n\nfrom django.conf import settings\n\nfrom .formatter import get_locale_formats\n\n\ndef timesince(timestamp, locale=None):\n    timedelta = datetime.now() - datetime.fromtimestamp(timestamp)\n    formatted = get_locale_formats(locale).timedelta(timedelta, format='long')\n    if formatted:\n        return formatted\n    return get_locale_formats(\n        settings.LANGUAGE_CODE).timedelta(timedelta, format='long')\n", "path": "pootle/i18n/dates.py"}]}