I am newbie in programming. Can you please help me to dispatch this url in python?

I want to dispatch a url of type: /algorithms/algorithm_name/topic/

I am working on django. This is what I tried:

    url(r'^(?P<topic_name>[a-zA-Z a-zA-Z a-zA-Z]+)/$',views.topic,name='topic'),

How to write the regex pattern for my url type?