The recent work on the cache_memoize() logic introduced some syntax

that's only compatible with Python 3.8. The code in question tried to

use the yield a, *b syntax to yield a tuple composed of a and the

contents of tuple b. This does not work in Python 3.7.
Instead, we're now using yield (a,) + b, which is the equivalent

behavior.

All unit tests pass on Python 3.7 through 3.10.