[NN] Attention Retrieval for NN Modules

[mufeili]

Description

It has been a common request from users to fetch attention values.

Checklist

Please feel free to remove inapplicable items for your PR.

• The PR title starts with [$CATEGORY] (such as [NN], [Model], [Doc], [Feature]])
• Changes are complete (i.e. I finished coding on this PR)
• All changes have test coverage
• Code is well-documented
• To the my best knowledge, examples are either not affected by this change,
  or have been fixed to be compatible with this change
• Related issue is referred in this PR

[VaticanCameos99]

Hey! Thanks for the update on the get_attention parameter. However, I recently installed dgl v0.5.3 on colab but this update wasn't relayed on it. Any idea what could be the issue?

[mufeili]

Hey! Thanks for the update on the get_attention parameter. However, I recently installed dgl v0.5.3 on colab but this update wasn't relayed on it. Any idea what could be the issue?

I think 0.5.3 does not include that. You need to install the nightly built version or install from source for the time being.

[VaticanCameos99]

Hey! Thanks for the update on the get_attention parameter. However, I recently installed dgl v0.5.3 on colab but this update wasn't relayed on it. Any idea what could be the issue?

I think 0.5.3 does not include that. You need to install the nightly built version or install from source for the time being.

Alright. Installing from source works. Thanks.