Myron

I mistake you code the really problem is in the code of users. ``` users = [ { "id": 0, "name": "Hero" }, { "id": 1, "name": "Dunn" }, {...

The output is like this: ``` most_common_interests_with(1) Out[88]: Counter() ``` Which is quit strange!

Indeed， the right code should be the following format: ``` python def most_common_interests_with(user_id): return Counter(interested_user_id for interest in interests_by_user_id[user_id] for interested_user_id in user_ids_by_interest[interest] if interested_user_id != user_id) ```

Oops！ I think there must be something you mistake when you write the final draft into the PDF for publishing. The code in PDF book Page 3 shows that id...

I have coded these codes following your book ``` num_friends_by_id = [(user["id"],number_of_friends(user)) for user in users] sorted(num_friends_by_id, key=lambda (users_id , num_friends): num_friends, reverse=True) ```

The output from `npz_keys.py` is as follow, `python npz.py snapshot_iter_410000.npz ['updater/model:main/model/extractor/base/res4/b4/conv2/bn/avg_mean', 'updater/optimizer:main/model/bbox_head/conf/b/v', 'updater/optimizer:main/model/bbox_head/conf/b/t', 'updater/optimizer:main/model/extractor/base/res2/b2/conv3/bn/beta/t', 'updater/optimizer:main/model/extractor/base/res3/a/residual_conv/bn/gamma/t', 'updater/iterator:main/order', 'updater/iterator:main/current_position', 'updater/optimizer:main/model/extractor/base/res4/a/conv3/conv/W/t', 'updater/optimizer:main/model/extractor/base/res3/b1/conv3/bn/beta/t', 'updater/optimizer:main/model/extractor/base/res2/a/conv3/bn/beta/t', 'updater/model:main/model/extractor/base/res2/b1/conv3/bn/avg_mean', 'updater/optimizer:main/model/extractor/base/res3/b2/conv2/bn/beta/t', 'updater/model:main/model/extractor/base/res3/a/residual_conv/bn/avg_var', 'updater/model:main/model/extractor/base/res4/b3/conv1/bn/N', 'updater/optimizer:main/model/bbox_head/loc/b/v', 'updater/model:main/model/extractor/base/res2/a/conv3/bn/avg_var', 'updater/optimizer:main/model/extractor/base/res2/b2/conv3/conv/W/t', 'updater/model:main/model/extractor/base/res2/a/conv3/bn/beta', 'updater/model:main/model/extractor/base/res3/a/conv2/bn/N', 'extension_triggers/_Snapshot_1/previous_iteration',...