Rip out all the u"..." literals and calls to unicode().
diff --git a/Lib/idlelib/PyShell.py b/Lib/idlelib/PyShell.py
index 692467d..2d69157 100644
--- a/Lib/idlelib/PyShell.py
+++ b/Lib/idlelib/PyShell.py
@@ -1008,7 +1008,7 @@
         line = self.text.get("iomark", "end-1c")
         if len(line) == 0:  # may be EOF if we quit our mainloop with Ctrl-C
             line = "\n"
-        if isinstance(line, unicode):
+        if isinstance(line, str):
             import IOBinding
             try:
                 line = line.encode(IOBinding.encoding)