How to fix Inkscape error No module named 'tinycss2' (Windows)

Some of the possibly relevant terms in similar errors: Traceback / import inkex / extensions / elements / _base import ShapeElement, BaseElement / .styles import Style, Classes, StyleValue / module / import tinycss2 / ModuleNotFoundError: No module named 'tinycss2'. Solution is to complete installation. Although I wouldn't use the perspective extension any more, related video TBD.