Apologies, but when I added the WeeWX v4 dependent specifics to wee_import I set the wee_import WeeWX version check to 4.0.0; however, the extended beta period resulted in more and more folks using one of the beta releases and of course according to distutils 4.0.0b12 < 4.0.0. I relaxed the version check to 4.0.0b1 as of 4.0.0b13, too late for your b12. You have three options:
1. edit your bin/wee_import and and change
to
REQUIRED_WEEWX = "4.0.0b1"
2. update to b13 or later
3. wait for WeeWX 4.0.0 to release
Gary