Don't try to convert str to Unicode anymore.
diff --git a/Lib/idlelib/OutputWindow.py b/Lib/idlelib/OutputWindow.py
index 4c07c03..0e8fd6d 100644
--- a/Lib/idlelib/OutputWindow.py
+++ b/Lib/idlelib/OutputWindow.py
@@ -35,16 +35,7 @@
# Act as output file
def write(self, s, tags=(), mark="insert"):
- # Tk assumes that byte strings are Latin-1;
- # we assume that they are in the locale's encoding
- if isinstance(s, str):
- try:
- s = str(s, IOBinding.encoding)
- except TypeError:
- raise
- except UnicodeError:
- # some other encoding; let Tcl deal with it
- pass
+ assert isinstance(s, str)
self.text.insert(mark, s, tags)
self.text.see(mark)
self.text.update()