Coverage: 99.48% (+0.0001%) from 99.48% when pulling92da690 on eriknw:chain_wait intoed6f3ba on python-graphblas:main.

This raises the question whether we should do the same forbuild,clear, and/orresize.

Nevermind, expressions shouldn't (and don't) havebuild/clear/resize, so these shouldn't returnself.expr.wait() doesn't actually modify the object, so havingval = expr.wait() can be a nice shorthand forval = expr.new().wait().