问‘'chatterbot’不是已注册的命名空间

EN

 var chatterbotUrl = '{% url "chatterbot:chatterbot" %}';

from django.conf.urls import url
from django.contrib import admin
from chatterbot.ext.django_chatterbot import urls as chatterbot_urls
from example_app.views import ChatterBotAppView, ChatterBotApiView


urlpatterns = [
    url(r'^$', ChatterBotAppView.as_view(), name='main'),
    url(r'^admin/', admin.site.urls, name='admin'),
    url(r'^api/chatterbot/', ChatterBotApiView.as_view(), name='chatterbot'),
]

Request Method: GET
Request URL:    http://127.0.0.1:8000/
Django Version: 2.1.2
Exception Type: NoReverseMatch
Exception Value:    
'chatterbot' is not a registered namespace
Python Version: 3.6.7