TypeError: unsupported operand type(s) for +: 'NoneType' and 'str'

[JakaSimonic]

While trying to Sync I get the following error. Is it a problem with the python version?

INFO:explorer.utils.schema:Downloading set(['ietf-yang-types', 'tailf-common']) ERROR:root:Could not parse modulename, uploaded file may be corrupted !! ERROR:root:Could not parse modulename, uploaded file may be corrupted !! [16/Mar/2018 14:07:21] ERROR [django.request] Internal Server Error: /explorer/schema Traceback (most recent call last): File "/home/jaka/Repos/yang-explorer/v/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 132, in get_response response = wrapped_callback(request, *callback_args, *callback_kwargs) File "/home/jaka/Repos/yang-explorer/server/explorer/views.py", line 303, in schema_handler return add_schema(request, req) File "/home/jaka/Repos/yang-explorer/server/explorer/utils/schema.py", line 213, in add_schema modules = download_yang(request, req) File "/home/jaka/Repos/yang-explorer/server/explorer/utils/schema.py", line 167, in download_yang new_fname = os.path.join(session_dir, parser.get_filename()) File "/home/jaka/Repos/yang-explorer/server/explorer/utils/yang.py", line 78, in get_filename return self.module + '.yang' TypeError: unsupported operand type(s) for +: 'NoneType' and 'str' ERROR:django.request:Internal Server Error: /explorer/schema Traceback (most recent call last): File "/home/jaka/Repos/yang-explorer/v/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 132, in get_response response = wrapped_callback(request, callback_args, **callback_kwargs) File "/home/jaka/Repos/yang-explorer/server/explorer/views.py", line 303, in schema_handler return add_schema(request, req) File "/home/jaka/Repos/yang-explorer/server/explorer/utils/schema.py", line 213, in add_schema modules = download_yang(request, req) File "/home/jaka/Repos/yang-explorer/server/explorer/utils/schema.py", line 167, in download_yang new_fname = os.path.join(session_dir, parser.get_filename()) File "/home/jaka/Repos/yang-explorer/server/explorer/utils/yang.py", line 78, in get_filename return self.module + '.yang' TypeError: unsupported operand type(s) for +: 'NoneType' and 'str'