Add some missing imports.

Fix some typos.
Fix some indentation errors.

docs/tutorial/3-class-based-views.md

@@ -7,11 +7,12 @@ We can also write our API views using class based views, rather than function ba
 We'll start by rewriting the root view as a class based view.  All this involves is a little bit of refactoring.
 
     from blog.models import Comment
-    from blog.serializers import ComentSerializer
+    from blog.serializers import CommentSerializer
     from django.http import Http404
     from djangorestframework.views import APIView
     from djangorestframework.response import Response
-    from djangorestframework.status import status
+    from djangorestframework import status
+
 
     class CommentRoot(APIView):
         """
@@ -19,16 +20,16 @@ We'll start by rewriting the root view as a class based view.  All this involves
         """
         def get(self, request, format=None):
             comments = Comment.objects.all()
-            serializer = ComentSerializer(instance=comments)
+            serializer = CommentSerializer(instance=comments)
             return Response(serializer.data)
 
-        def post(self, request, format=None)
-            serializer = ComentSerializer(request.DATA)
+        def post(self, request, format=None):
+            serializer = CommentSerializer(request.DATA)
             if serializer.is_valid():
                 comment = serializer.object
                 comment.save()
-                return Response(serializer.serialized, status=HTTP_201_CREATED)
-            return Response(serializer.serialized_errors, status=HTTP_400_BAD_REQUEST)
+                return Response(serializer.serialized, status=status.HTTP_201_CREATED)
+            return Response(serializer.serialized_errors, status=status.HTTP_400_BAD_REQUEST)
 
     comment_root = CommentRoot.as_view()