creditorでファイルアップロードして名前を変更するときにエラーが出る。

creditorでファイルアップロードして名前を変更するときにエラーが出ます。
djangoにこのgithubの説明に従ってckeditorを導入しました。
RichTextUploadingField()を使って画像をアップロードすることには成功したのですが、アップロード時に画像の名前を変更するため先ほどのgithubの「Required for using widget with file upload」の章のに従っところ以下のエラーが出てきてしまいます。

python manage.py runserver の所

Internal Server Error: /ckeditor/upload/
Traceback (most recent call last):
  File "/Users/username/.pyenv/versions/anaconda3-4.3.0/envs/python27/lib/python2.7/site-packages/django/core/handlers/exception.py", line 41, in inner
    response = get_response(request)
  File "/Users/username/.pyenv/versions/anaconda3-4.3.0/envs/python27/lib/python2.7/site-packages/django/core/handlers/base.py", line 187, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/Users/username/.pyenv/versions/anaconda3-4.3.0/envs/python27/lib/python2.7/site-packages/django/core/handlers/base.py", line 185, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/Users/username/.pyenv/versions/anaconda3-4.3.0/envs/python27/lib/python2.7/site-packages/django/contrib/auth/decorators.py", line 23, in _wrapped_view
    return view_func(request, *args, **kwargs)
  File "/Users/username/.pyenv/versions/anaconda3-4.3.0/envs/python27/lib/python2.7/site-packages/django/views/decorators/csrf.py", line 58, in wrapped_view
    return view_func(*args, **kwargs)
  File "/Users/username/.pyenv/versions/anaconda3-4.3.0/envs/python27/lib/python2.7/site-packages/django/views/generic/base.py", line 68, in view
    return self.dispatch(request, *args, **kwargs)
  File "/Users/username/.pyenv/versions/anaconda3-4.3.0/envs/python27/lib/python2.7/site-packages/django/views/generic/base.py", line 88, in dispatch
    return handler(request, *args, **kwargs)
  File "/Users/username/Sites/myproject/ckeditor_uploader/views.py", line 87, in post
    saved_path = self._save_file(request, uploaded_file)
  File "/Users/username/Sites/myproject/ckeditor_uploader/views.py", line 105, in _save_file
    filename = get_upload_filename(uploaded_file.name, request.user)
  File "/Users/username/Sites/myproject/ckeditor_uploader/views.py", line 54, in get_upload_filename
    generator = import_string(settings.CKEDITOR_FILENAME_GENERATOR)
  File "/Users/username/.pyenv/versions/anaconda3-4.3.0/envs/python27/lib/python2.7/site-packages/django/utils/module_loading.py", line 20, in import_string
    module = import_module(module_path)
  File "/Users/username/.pyenv/versions/anaconda3-4.3.0/envs/python27/lib/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
ImportError: No module named utils
[19/Jul/2017 16:21:45] "POST /ckeditor/upload/?CKEditor=id_body&CKEditorFuncNum=153&langCode=ja HTTP/1.1"