error log

ERROR 2019-09-01 12:11:39,548 exception Internal Server Error: /
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/django/core/handlers/exception.py", line 41, in inner
    response = get_response(request)
  File "/usr/lib/python3/dist-packages/django/core/handlers/base.py", line 172, in _get_response
    resolver_match = resolver.resolve(request.path_info)
  File "/usr/lib/python3/dist-packages/django/urls/resolvers.py", line 364, in resolve
    for pattern in self.url_patterns:
  File "/usr/lib/python3/dist-packages/django/utils/functional.py", line 35, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/usr/lib/python3/dist-packages/django/urls/resolvers.py", line 407, in url_patterns
    patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
  File "/usr/lib/python3/dist-packages/django/utils/functional.py", line 35, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/usr/lib/python3/dist-packages/django/urls/resolvers.py", line 400, in urlconf_module
    return import_module(self.urlconf_name)
  File "/usr/lib/python3.5/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 986, in _gcd_import
  File "<frozen importlib._bootstrap>", line 969, in _find_and_load
  File "<frozen importlib._bootstrap>", line 958, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 673, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 673, in exec_module
  File "<frozen importlib._bootstrap>", line 222, in _call_with_frames_removed
  File "/usr/lib/python3/dist-packages/lava_server/urls.py", line 125, in <module>
    include("lava_rest_app.urls"),
  File "/usr/lib/python3/dist-packages/django/conf/urls/__init__.py", line 50, in include
    urlconf_module = import_module(urlconf_module)
  File "/usr/lib/python3.5/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 986, in _gcd_import
  File "<frozen importlib._bootstrap>", line 969, in _find_and_load
  File "<frozen importlib._bootstrap>", line 958, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 673, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 673, in exec_module
  File "<frozen importlib._bootstrap>", line 222, in _call_with_frames_removed
  File "/usr/lib/python3/dist-packages/lava_rest_app/urls.py", line 22, in <module>
    from . import api
  File "/usr/lib/python3/dist-packages/lava_rest_app/api.py", line 32, in <module>
    from rest_framework import routers, serializers, views, viewsets
  File "/usr/lib/python3/dist-packages/rest_framework/routers.py", line 28, in <module>
    from rest_framework.schemas import SchemaGenerator
  File "/usr/lib/python3/dist-packages/rest_framework/schemas.py", line 4, in <module>
    from django.contrib.admindocs.views import simplify_regex
  File "/usr/lib/python3/dist-packages/django/contrib/admindocs/views.py", line 9, in <module>
    from django.contrib.admindocs import utils
  File "/usr/lib/python3/dist-packages/django/contrib/admindocs/utils.py", line 13, in <module>
    import docutils.core
  File "/usr/lib/python3/dist-packages/docutils/core.py", line 20, in <module>
    from docutils import frontend, io, utils, readers, writers
  File "/usr/lib/python3/dist-packages/docutils/frontend.py", line 41, in <module>
    import docutils.utils
  File "/usr/lib/python3/dist-packages/docutils/utils/__init__.py", line 20, in <module>
    import docutils.io
  File "/usr/lib/python3/dist-packages/docutils/io.py", line 18, in <module>
    from docutils.utils.error_reporting import locale_encoding, ErrorString, ErrorOutput
  File "/usr/lib/python3/dist-packages/docutils/utils/error_reporting.py", line 60, in <module>
    codecs.lookup(locale_encoding or '') # None -> ''
NameError: name 'locale_encoding' is not defined