diff --git a/qutebrowser/utils/qtutils.py b/qutebrowser/utils/qtutils.py
index b504b1803..7decba942 100644
--- a/qutebrowser/utils/qtutils.py
+++ b/qutebrowser/utils/qtutils.py
@@ -247,6 +247,7 @@ class PyQIODevice(io.BufferedIOBase):
     # pylint: disable=missing-docstring
 
     def __init__(self, dev):
+        super().__init__()
         self.dev = dev
 
     def __len__(self):
diff --git a/qutebrowser/utils/utils.py b/qutebrowser/utils/utils.py
index 3e4740c0d..01723c704 100644
--- a/qutebrowser/utils/utils.py
+++ b/qutebrowser/utils/utils.py
@@ -419,6 +419,7 @@ class FakeIOStream(io.TextIOBase):
     """A fake file-like stream which calls a function for write-calls."""
 
     def __init__(self, write_func):
+        super().__init__()
         self.write = write_func
 
     def flush(self):