old_contents: # coding: utf-8
  from __future__ import unicode_literals
  
  from django.core.management.base import AppCommand, CommandError
  from django.db.models import get_models
  from ckeditor.fields import RichTextField
  
  from ckeditor_media.utils import create_thumbs
  
  
  class Command(AppCommand):
      help = 'Generate thumbs for models of app'
  
      def handle_app(self, app, **kwargs):
          for model in get_models(app):
              affected_fields = [f.name for f in model._meta.fields
                                 if isinstance(f, RichTextField)]
  
              if not affected_fields:
                  continue
  
              self.proccess(model, affected_fields)
  
      def proccess(self, model, fields):
          i = 0
          for i, obj in enumerate(model.objects.all()):
              for fname in fields:
                  setattr(obj, fname, create_thumbs(getattr(obj, fname)))
              obj.save()
  
          print('>> {} {} updated'.format(i, repr(model)))
  
new_contents: # coding: utf-8
  from __future__ import unicode_literals
  
  from django.core.management.base import AppCommand, CommandError
  from django.db.models import get_models
  from django.db.models import TextField
  
  from sorl_hacks.utils import create_thumbs
  
  
  class Command(AppCommand):
      help = 'Generate thumbs for models of app'
  
      def handle_app(self, app, **kwargs):
          for model in get_models(app):
              affected_fields = [f.name for f in model._meta.fields
                                 if isinstance(f, TextField)]
  
              if not affected_fields:
                  continue
  
              self.proccess(model, affected_fields)
  
      def proccess(self, model, fields):
          i = 0
          for i, obj in enumerate(model.objects.all()):
              for fname in fields:
                  setattr(obj, fname, create_thumbs(getattr(obj, fname)))
              obj.save()
  
          print('>> {} {} updated'.format(i, repr(model)))
  
subject: rename module in cmd