Class docs

[ajberdy]

Issue #, if available:

Description of changes:

Add class docstring to circuit subroutines

Testing done:

docs inspection

Merge Checklist

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General

• [x] I have read the CONTRIBUTING doc
• [x] I used the commit message format described in CONTRIBUTING
• [x] I have updated any necessary documentation, including READMEs and API docs (if appropriate)

Tests

• [x] I have added tests that prove my fix is effective or that my feature works (if appropriate)
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