old_contents: from django.contrib import admin
  
  import reversion
  
  from calebasse.personnes.models import (Holiday, People, TimeTable,
          SchoolTeacher, UserWorker, Worker, Role)
  
  admin.site.register(Holiday, reversion.VersionAdmin)
  admin.site.register(People, reversion.VersionAdmin)
  admin.site.register(TimeTable, reversion.VersionAdmin)
  admin.site.register(SchoolTeacher, reversion.VersionAdmin)
  admin.site.register(UserWorker, reversion.VersionAdmin)
  admin.site.register(Worker, reversion.VersionAdmin)
  admin.site.register(Role, reversion.VersionAdmin)
  
new_contents: from django.contrib import admin
  
  import reversion
  
  from calebasse.personnes.models import (Holiday, People, TimeTable,
          SchoolTeacher, UserWorker, Worker, ExternalWorker,
          ExternalTherapist, Role)
  
  admin.site.register(Holiday, reversion.VersionAdmin)
  admin.site.register(People, reversion.VersionAdmin)
  admin.site.register(TimeTable, reversion.VersionAdmin)
  admin.site.register(SchoolTeacher, reversion.VersionAdmin)
  admin.site.register(UserWorker, reversion.VersionAdmin)
  admin.site.register(Worker, reversion.VersionAdmin)
  admin.site.register(ExternalWorker, reversion.VersionAdmin)
  admin.site.register(ExternalTherapist, reversion.VersionAdmin)
  admin.site.register(Role, reversion.VersionAdmin)
  
subject: add externs to admin.