Fix a bizarre error where test_pickletools fails if preceded by test_pyclbr.
The fix is in neither, but in pickle.py where a loop over sys.modules.items()
could modify sys.modules, occasionally.
diff --git a/Lib/pickle.py b/Lib/pickle.py
index db7f512..3d2ebd2 100644
--- a/Lib/pickle.py
+++ b/Lib/pickle.py
@@ -791,7 +791,7 @@
if func in classmap:
return classmap[func]
- for name, module in sys.modules.items():
+ for name, module in list(sys.modules.items()):
if module is None:
continue # skip dummy package entries
if name != '__main__' and getattr(module, funcname, None) is func: