NoReverseMatch error from Python Tutorial - python-3.7

Question

Django Tutorial part 4 I am getting a NoReverseMatch at /polls/1/
NoReverseMatch at /polls/1/
Reverse for 'polls.index' not found. 'polls.index' is not a valid view
In template /var/www/html/django_app/polls/templates/polls/detail.html, error at line 5
Reverse for 'polls.index' not found. 'polls.index' is not a valid view function or pattern name...
I have looked up and researched this question on here for a while and am hitting a wall. There are many references to the problem but none that match the problem I am seeing and the state of my current code.
urls.py
from django.urls import path
from . import views
app_name = 'polls'
urlpatterns = [
path('', views.IndexView.as_view(), name='index'),
path('<int:pk>/', views.DetailView.as_view(), name='detail'),
path('<int:pk>/results/', views.ResultsView.as_view(), name='results'),
path('<int:question_id>/vote/', views.vote, name='vote'),
]
detail.py
<h1>{{ question.question_text }}</h1>
{% if error_message %}<p><strong>{{ error_message }}</strong></p>{% endif %}
<form action="{% url 'polls.vote' question.id %}" method="post">
{% csrf_token %}
{% for choice in question.choice_set.all %}
<input type="radio" name="choice" id="choice{{ forloop.counter }}" value="{{ choice.id }}">
<label for="choice{{ forloop.counter }}">{{ choice.choice_text }</label><br>
{% endfor %}
<input type="submit" value="Vote">
</form>
views.py
class IndexView(generic.ListView):
template_name = 'polls/index.html'
context_object_name = 'latest_question_list'
def get_queryset(self):
return Question.objects.order_by('-pub_date')[:5]
class DetailView(generic.DetailView):
model = Question
template_name = 'polls/detail.html'
class ResultsView(generic.DetailView):
model = Question
template_name = 'polls/detail.html'
def vote(request, question_id):
question = get_object_or_404(Question, pk=question_id)
try:
selected_choice = question.choice_set.get(pk=request.POST['choice'])
except (KeyError, Choice.DoesNotExist):
# Redisplay the question voting form.
return render(request, 'polls/detail.html', {
'question': question,
'error_message': "You didn't select a choice.",
})
else:
selected_choice.votes += 1
selected_choice.save()
# Always return and HttpResponseRedirect after successfully dealin
# with POST data. This prevents data from being posted twice if a
# user hits the Back button.
return HttpResponseRedirect(reverse('polls:results', args=(question.id,)))
I can clearly see what it saying the problem is but I can't seem to determine what is causing it.
Any extra eyes would help and be greatly appreciated!