Keep references for oldkey and oldvalue so they can't
trigger a __del__ method to reenter our thread.

Move the cache[key]=link step to the end, after the link
data is in a consistent state.

Under exotic circumstances, the cache[key]=link step could
trigger reentrancy (i.e. the key would have to have a hash
exactly equal to that for another key in the cache and the
key would need a __eq__ method that makes a reentrant call
our cached function).

This removes the dependency on bisect and it bring the pure Python code
in-sync with the C code.

in the subprocess module on Linux.

the subprocess module on Linux.

#17032: The "global" in the "NameError: global name 'x' is not defined" error message has been removed.  Patch by Ram Rachum.

#16935: unittest now counts the module as skipped if it raises SkipTest, instead of counting it as an error.  Patch by Zachary Ware.