Internal Server Error: /home/map/2/2015-08-06/

[Baguage]

How to reproduce:
https://zika.vecnet.org/home/map/2/2015-08-06

Stacktrace:
TypeError at /home/map/2/2015-08-06/
'NoneType' object is not subscriptable

File "/opt/venv/zika.vecnet.org/lib/python3.5/site-packages/django/core/handlers/exception.py" in inner
39. response = get_response(request)

File "/opt/venv/zika.vecnet.org/lib/python3.5/site-packages/django/core/handlers/base.py" in _legacy_get_response
249. response = self._get_response(request)

File "/opt/venv/zika.vecnet.org/lib/python3.5/site-packages/django/core/handlers/base.py" in _get_response
187. response = self.process_exception_by_middleware(e, request)

File "/opt/venv/zika.vecnet.org/lib/python3.5/site-packages/django/core/handlers/base.py" in _get_response
185. response = wrapped_callback(request, *callback_args, **callback_kwargs)

File "/opt/venv/zika.vecnet.org/lib/python3.5/site-packages/django/views/generic/base.py" in view
68. return self.dispatch(request, *args, **kwargs)

File "/opt/venv/zika.vecnet.org/lib/python3.5/site-packages/django/views/generic/base.py" in dispatch
88. return handler(request, *args, **kwargs)

File "/opt/venv/zika.vecnet.org/lib/python3.5/site-packages/django/views/generic/base.py" in get
155. context = self.get_context_data(**kwargs)

File "/opt/portal/zika.vecnet.org/website/apps/home/views/MapView.py" in get_context_data
51. pdate = datetime.date(int(prev_date[0:4]), int(prev_date[5:7]), int(prev_date[8:]))

Exception Type: TypeError at /home/map/2/2015-08-06/
Exception Value: 'NoneType' object is not subscriptable