diff --git a/gallery_dl/extractor/mangahere.py b/gallery_dl/extractor/mangahere.py
index 97c26d473a..745231b1dd 100644
--- a/gallery_dl/extractor/mangahere.py
+++ b/gallery_dl/extractor/mangahere.py
@@ -114,8 +114,7 @@ class MangahereMangaExtractor(MangahereBase, MangaExtractor):
         ("https://m.mangahere.co/manga/aria/"),
     )
 
-    def __init__(self, match):
-        MangaExtractor.__init__(self, match)
+    def _init(self):
         self.cookies.set("isAdult", "1", domain="www.mangahere.cc")
 
     def chapters(self, page):
diff --git a/gallery_dl/extractor/tumblr.py b/gallery_dl/extractor/tumblr.py
index 12ea39f8c5..9adc3ab137 100644
--- a/gallery_dl/extractor/tumblr.py
+++ b/gallery_dl/extractor/tumblr.py
@@ -442,10 +442,13 @@ class TumblrDayExtractor(TumblrExtractor):
     def __init__(self, match):
         TumblrExtractor.__init__(self, match)
         year, month, day = match.group(4).split("/")
-        self.date_min = ts = (
+        self.date_min = (
             # 719163 == date(1970, 1, 1).toordinal()
             date(int(year), int(month), int(day)).toordinal() - 719163) * 86400
-        self.api.before = ts + 86400
+
+    def _init(self):
+        TumblrExtractor._init(self)
+        self.api.before = self.date_min + 86400
 
     def posts(self):
         return self.api.posts(self.blog, {})
diff --git a/test/test_extractor.py b/test/test_extractor.py
index 6516fa8f62..e328664708 100644
--- a/test/test_extractor.py
+++ b/test/test_extractor.py
@@ -132,8 +132,16 @@ def test_unique_pattern_matches(self):
             else:
                 self.assertIs(extr1, matches[0][1], url)
 
+    def test_init(self):
+        """Test for exceptions in Extractor.initialize(()"""
+        for cls in extractor.extractors():
+            for test in cls._get_tests():
+                extr = cls.from_url(test[0])
+                extr.initialize()
+                break
+
     def test_docstrings(self):
-        """ensure docstring uniqueness"""
+        """Ensure docstring uniqueness"""
         for extr1 in extractor.extractors():
             for extr2 in extractor.extractors():
                 if extr1 != extr2 and extr1.__doc__ and extr2.__doc__: