getting sizes (amount of content) for each subject in khan academy

contentsize.py

# getting relative size of each subject in math using
# http://www.khanacademy.org/api/v1/topictree and helper
# methods from https://gist.github.com/nsfmc/2a877c61f0f7da984ead
# to plug into something like https://gist.github.com/nsfmc/2d496c1bb9e096402f8e

output = []
for s in subjects_for_domain('math'):
    count = 0
    for t in get_topics(domain='math', subject=s['slug']):
        for tut in t['children']:
            count += len(tut['children']) if tut.get('children') else 0
    output.append('name': s['title'], 'size': count})
print json.dumps(output)