[python mode] Make sure the base scope is never dropped
[python mode] Make sure the base scope is never dropped

Closes #4105

kerabromsmu/CodeMirror,schanzer/CodeMirror,grzegorzmazur/CodeMirror,mtaran-google/CodeMirror,notepadqq/CodeMirror,Dominator008/CodeMirror,TDaglis/CodeMirror,INTELOGIE/CodeMirror,MarcelGerber/CodeMirror,thomasjm/CodeMirror,jkaplon/CodeMirror,ficristo/CodeMirror,ejgallego/CodeMirror,xeronith/CodeMirror,Dominator008/CodeMirror,ficristo/CodeMirror,pabloferz/CodeMirror,SidPresse/CodeMirror,adobe/CodeMirror2,alur/CodeMirror,mizchi/CodeMirror,INTELOGIE/CodeMirror,SidPresse/CodeMirror,nightwing/CodeMirror,dperetti/CodeMirror,rrandom/CodeMirror,MarcelGerber/CodeMirror,sourcelair/CodeMirror,crazy4chrissi/CodeMirror,sourcelair/CodeMirror,codio/CodeMirror,wingify/CodeMirror,wingify/CodeMirror,INTELOGIE/CodeMirror,codio/CodeMirror,mtaran-google/CodeMirror,dperetti/CodeMirror,kerabromsmu/CodeMirror,jayaprabhakar/CodeMirror,thomasjm/CodeMirror,crazy4chrissi/CodeMirror,TDaglis/CodeMirror,xeronith/CodeMirror,mtaran-google/CodeMirror,codio/CodeMirror,schanzer/CodeMirror,alur/CodeMirror,TDaglis/CodeMirror,schanzer/CodeMirror,hackmdio/CodeMirror,thomasjm/CodeMirror,notepadqq/CodeMirror,nightwing/CodeMirror,pabloferz/CodeMirror,alur/CodeMirror,namin/CodeMirror,SidPresse/CodeMirror,MarcelGerber/CodeMirror,jkaplon/CodeMirror,xeronith/CodeMirror,namin/CodeMirror,wingify/CodeMirror,hackmdio/CodeMirror,sourcelair/CodeMirror,dperetti/CodeMirror,rrandom/CodeMirror,jkaplon/CodeMirror,ficristo/CodeMirror,mizchi/CodeMirror,crazy4chrissi/CodeMirror,adobe/CodeMirror2,Dominator008/CodeMirror,jayaprabhakar/CodeMirror,grzegorzmazur/CodeMirror,namin/CodeMirror,ejgallego/CodeMirror,nightwing/CodeMirror,mizchi/CodeMirror,notepadqq/CodeMirror,grzegorzmazur/CodeMirror,hackmdio/CodeMirror,kerabromsmu/CodeMirror,pabloferz/CodeMirror,rrandom/CodeMirror,jayaprabhakar/CodeMirror,adobe/CodeMirror2,ejgallego/CodeMirror