old_contents: from django.http import HttpResponseBadRequest
  from django.contrib import auth
  
  
  class TokenMiddleware(object):
      """
      Middleware that authenticates against a token in the http authorization header.
      """
  
      def process_request(self, request):
          auth_header = request.META.get('HTTP_AUTHORIZATION', b'').split()
  
          if not auth_header or auth_header[0].lower() != b'token':
              return None
  
          # If they specified an invalid token, let them know.
          if len(auth_header) != 2:
              return HttpResponseBadRequest("Improperly formatted token")
  
          user = auth.authenticate(token=auth_header[1])
          if user:
              request.user = user
  
new_contents: from django.http import HttpResponseBadRequest
  from django.contrib import auth
  
  
  class TokenMiddleware(object):
      """
      Middleware that authenticates against a token in the http authorization header.
      """
  
      def process_request(self, request):
          auth_header = request.META.get('HTTP_AUTHORIZATION', b'').partition(' ')
  
          if auth_header[0].lower() != b'token':
              return None
  
          # If they specified an invalid token, let them know.
          if not auth_header[2]:
              return HttpResponseBadRequest("Improperly formatted token")
  
          user = auth.authenticate(token=auth_header[2])
          if user:
              request.user = user
  
subject: Use partition instead of split.