fix https://github.com/sagemathinc/cocalc/issues/2828
fix https://github.com/sagemathinc/cocalc/issues/2828

DrXyzzy/smc,DrXyzzy/smc,sagemathinc/smc,tscholl2/smc,sagemathinc/smc,DrXyzzy/smc,tscholl2/smc,sagemathinc/smc,tscholl2/smc,tscholl2/smc,DrXyzzy/smc,tscholl2/smc,sagemathinc/smc