problem in first part of polls app

Can somebody hlep me out with this?
This the error I get when i run the polls app

NameError at /polls/

global name 'HttpResponse' is not defined

Request Method:	GET
Request URL:	http://127.0.0.1:8000/polls/
Django Version:	1.9
Exception Type:	NameError
Exception Value:	global name 'HttpResponse' is not defined
Exception Location:	/home/yogitha/Desktop/mysite/polls/views.py in index, line 6
Python Executable:	/usr/bin/python
Python Version:	2.7.6
Python Path:	['/home/yogitha/Desktop/mysite', '/usr/lib/python2.7', '/usr/lib/python2.7/plat-x86_64-linux-gnu', '/usr/lib/python2.7/lib-tk', '/usr/lib/python2.7/lib-old', '/usr/lib/python2.7/lib-dynload', '/usr/local/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages/PILcompat', '/usr/lib/python2.7/dist-packages/gtk-2.0', '/usr/lib/python2.7/dist-packages/ubuntu-sso-client']
Server time:	Mon, 7 Dec 2015 16:35:58 +0000

Please tell me what needs to be done

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