jupyter: make previous patch more paranoid.
jupyter: make previous patch more paranoid.

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