From 0b4be57a10047d1b60d97be00f5e08b240babee4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mike=20F=C3=A4hrmann?= <mike_faehrmann@web.de>
Date: Tue, 14 May 2019 23:40:07 +0200
Subject: [PATCH] [sankaku] fix error when no tags available (closes #259)

[ci skip]
---
 gallery_dl/extractor/sankaku.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gallery_dl/extractor/sankaku.py b/gallery_dl/extractor/sankaku.py
index 8c3bbb35..e0d519c3 100644
--- a/gallery_dl/extractor/sankaku.py
+++ b/gallery_dl/extractor/sankaku.py
@@ -101,7 +101,7 @@ class SankakuExtractor(SharedConfigMixin, Extractor):
             tags = collections.defaultdict(list)
             tags_html = text.extract(page, '<ul id=tag-sidebar>', '</ul>')[0]
             pattern = re.compile(r'tag-type-([^>]+)><a href="/\?tags=([^"]+)')
-            for tag_type, tag_name in pattern.findall(tags_html):
+            for tag_type, tag_name in pattern.findall(tags_html or ""):
                 tags[tag_type].append(text.unquote(tag_name))
             for key, value in tags.items():
                 data["tags_" + key] = " ".join(value)