Finally, after more than a year and a half of the pandemic theater blackout, I received an invitation for a press opening night to a live stage production at Theatre Wit, 1229 W. Belmont.It was for “Mr. Burns, A Post-Electric Play” by Anna Washburn, who also wrote lyrics, with a musical score by Michael Friedman.Directed by Jeremy Wechsler, it is a recycling of the company’s three-act 2015 production, which I had not seen. The current version is in an open run.I had heard that it was about how a group of …