Issue #18471: Fix typo in heapq documentation (reported by Fran?ois Pinard).
check the return value of new_string() (closes #18470)
move declaration to top of block
Issue #17778: Fix test discovery for test_multiprocessing. (Patch by
Zachary Ware.)
Closes #18475: add unittest.main() to test_email/test_inversions.

Patch by Vajrasky Kok.
Issue #18457: Fixed saving of formulas and complex numbers in Tools/demo/ss1.py.
Useed context managers for file I/O.
Removed out-of-dated code and misleading comments.
Issue #18448: Fix a typo in Tools/demo/eiffel.py.