Django：自定义中间件导致NoneType错误

我有这个错误：

Internal Server Error: /
    Traceback (most recent call last):
      File "/home/cena/AjiiMajii/.venv/local/lib/python2.7/site-packages/django/core/handlers/exception.py", line 41, in inner
        response = get_response(request)
      File "/home/cena/AjiiMajii/.venv/local/lib/python2.7/site-packages/django/utils/deprecation.py", line 142, in __call__
        response = self.process_response(request, response)
      File "/home/cena/AjiiMajii/.venv/local/lib/python2.7/site-packages/django/middleware/clickjacking.py", line 32, in process_response
        if response.get('X-Frame-Options') is not None:
    AttributeError: 'NoneType' object has no attribute 'get'
    [04/Dec/2017 20:08:25] "GET / HTTP/1.1" 500 65880

my middleware is :

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',
    'cms.Middleware.Visits',
]

</pre>
 

 and my custom middleware 'cms.Middleware.Visits' 
    

class Visits(MiddlewareMixin):
    def __init__(self,get_response):
        self.get_response = get_response
    def __call__(self, request):
            print '*'*22
            print self.get_client_ip(request)
            print '*'*22

    def get_client_ip(self,request):
        x_forwarded_for = request.META.get('HTTP_X_FORWARDED_FOR')
        if x_forwarded_for:
            ip = x_forwarded_for.split(',')[-1].strip()
        else:
            ip = request.META.get('REMOTE_ADDR')
        return ip
    def RedisConnection(self):
        Connection=redis.Redis(host='localhost',port='6379')
        self.Connection=Connection
        return     self.Connection
    def IpCheker(self):
        # just set and count of visit[s] for ever ip 
        print '%'*30
        print self.get_client_ip()
        print '%'*30
        self.RedisConnection()
        if self.Connection.get(self.CliReq):
            HashPattern=self.HashSetter(self.CliReq)
            UserId=self.Connection.get(self.CliReq)
            UserPattern="User:Id:{}".format(UserId)
            print UserPattern
            self.Connection.hincrby(UserPattern,'vcount')
        else:
            IDnum=self.IdGenerator(self.CliReq)
            self.Connection.set(self.CliReq,IDnum)
            HashPattern=self.HashSetter(self.CliReq)
            Location=self.GetLoc(self.CliReq)
            self.Connection.hset(HashPattern,'ip',self.CliReq)
            self.Connection.hset(HashPattern,'vcount',1)
            self.Connection.hset(HashPattern,'loc',Location)
    def HashSetter(self,ip):
         id=self.IdGenerator(ip)
         IdStyle='User:Id:{}'.format(id)
         return IdStyle
    def IdGenerator(self,ip):
        Count=self.Connection.keys('User:Id:*')
        id= len(Count) + 1
        return id
    def GetLoc(self,ip):
        #GetLocation oF ip's
        print 'f' * 80
        ApiLoc='http://www.freegeoip.net/json/'
        ABSLOC=requests.get('http://www.freegeoip.net/json/{}'.format(ip))
        LocInfo=json.loads(ABSLOC.content)
        return LocInfo['country_name']

</pre>

我无法解决或调试这个，为什么会发生这种情况？