NoReverseMatch at / Reverse for 'course_detail' with arguments '('',)' not found. 1 pattern(s) tried: ['course/(?P[-a-zA-Z0-9_]+)/$']

Question

I am trying to make a site that has a learning area so that instructors can upload courses for users to look at. i am trying to add a url to the home page to link to te cour