@deinspanjer (issue #164) discovered that VisiData doesn't work with Python3.7 due to our use of the 'async' identifier, which is now off-limits as it is a formal keyword as of 3.7. The only change in 1.2.1 is changing 'async' to 'asyncthread' in order to work with Python 3.7.
Thanks to the illustrious @anjakefala for getting this release out quickly and without incident (knock on wood).