title: expected str, bytes or os.PathLike object, not NoneType
body: <p>I got this code which is supposed to create a folder based on the logged in users name and save the file they upload inside that folder.</p>
  
  <p>My problem is that it throws this error code </p>
  
  <blockquote>
    <p>expected str, bytes or os.PathLike object, not NoneType</p>
  </blockquote>
  
  <p>My current code:</p>
  
  <pre><code>def user_directory_path(instance, filename):
      time_stamp = 'user_{0}/{1}'.format(instance.user, filename)
      createfolder = os.path.join('C:/Users/MyUser/Desktop/Project/', 'Fileuploads/', time_stamp,)
      if not os.path.exists(createfolder):
          os.makedirs(createfolder)
  </code></pre>
  
  <p>Traceback:</p>
  
  <pre><code>Environment:
  
  
  Request Method: POST Request URL: http://127.0.0.1:8000/callgolem/
  
  Django Version: 2.0.4 Python Version: 3.6.5 Installed Applications: ['django.contrib.admin',  'django.contrib.auth',  'django.contrib.contenttypes',  'django.contrib.sessions',  'django.contrib.messages',  'django.contrib.staticfiles',  'callgolem'] Installed Middleware: ['django.middleware.security.SecurityMiddleware',  'django.contrib.sessions.middleware.SessionMiddleware',  'django.middleware.common.CommonMiddleware',  'django.middleware.csrf.CsrfViewMiddleware',  'django.contrib.auth.middleware.AuthenticationMiddleware',  'django.contrib.messages.middleware.MessageMiddleware',  'django.middleware.clickjacking.XFrameOptionsMiddleware']
  
  
  
  
  
  File "C:\Users\wqe\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\core\handlers\exception.py" in inner
    35.             response = get_response(request)
  
  File "C:\Users\wqe\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\core\handlers\base.py" in _get_response
    128.                 response = self.process_exception_by_middleware(e, request)
  
  File "C:\Users\wqe\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\core\handlers\base.py" in _get_response
    126.                 response = wrapped_callback(request, *callback_args, **callback_kwargs)
  
  File "C:\Users\wqe\Desktop\GolemProject\callgolem\views.py" in index
    65.                 instance.save()
  
  File "C:\Users\wqe\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\db\models\base.py" in save
    729.                        force_update=force_update, update_fields=update_fields)
  
  File "C:\Users\wqe\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\db\models\base.py" in save_base
    759.             updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
  
  File "C:\Users\wqe\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\db\models\base.py" in _save_table
    842.             result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
  
  File "C:\Users\wqe\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\db\models\base.py" in _do_insert
    880.                                using=using, raw=raw)
  
  File "C:\Users\wqe\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\db\models\manager.py" in manager_method
    82.                 return getattr(self.get_queryset(), name)(*args, **kwargs)
  
  File "C:\Users\wqe\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\db\models\query.py" in _insert
    1125.         return query.get_compiler(using=using).execute_sql(return_id)
  
  File "C:\Users\wqe\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\db\models\sql\compiler.py" in execute_sql
    1283.             for sql, params in self.as_sql():
  
  File "C:\Users\wqe\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\db\models\sql\compiler.py" in as_sql
    1236.                 for obj in self.query.objs
  
  File "C:\Users\wqe\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\db\models\sql\compiler.py" in &lt;listcomp&gt;
    1236.                 for obj in self.query.objs
  
  File "C:\Users\wqe\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\db\models\sql\compiler.py" in &lt;listcomp&gt;
    1235.                 [self.prepare_value(field, self.pre_save_val(field, obj)) for field in fields]
  
  File "C:\Users\wqe\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\db\models\sql\compiler.py" in pre_save_val
    1185.         return field.pre_save(obj, add=True)
  
  File "C:\Users\wqe\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\db\models\fields\files.py" in pre_save
    287.             file.save(file.name, file.file, save=False)
  
  File "C:\Users\wqe\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\db\models\fields\files.py" in save
    86.         name = self.field.generate_filename(self.instance, name)
  
  File "C:\Users\wqe\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\db\models\fields\files.py" in generate_filename
    306.         return self.storage.generate_filename(filename)
  
  File "C:\Users\wqe\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\core\files\storage.py" in generate_filename
    97.         dirname, filename = os.path.split(filename)
  
  File "C:\Users\wqe\AppData\Local\Programs\Python\Python36-32\lib\ntpath.py" in split
    205.     p = os.fspath(p)
  
  Exception Type: TypeError at /callgolem/ Exception Value: expected str, bytes or os.PathLike object, not NoneType
  </code></pre>