Check row.magazines.length

It appears that row.magazines is an array. In which case checking the length of the array is necessary.
Check row.magazines.length

Updating python documentation per @neumino request
https://github.com/rethinkdb/docs/pull/397#issuecomment-47954597
Check row.magazines.length

Updating python documentation per @neumino request
https://github.com/rethinkdb/docs/pull/397#issuecomment-47954597
Merge pull request #397 from brettgriffin/patch-1

Fix for r.js - PR by @brettgriffin