add Self type

[russbiggs]

resolves #105

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.55%. Comparing base (a3de67c) to head (bcfe964).

Additional details and impacted files

@@            Coverage Diff             @@
##           v1.2.0     #116      +/-   ##
==========================================
+ Coverage   95.42%   95.55%   +0.13%     
==========================================
  Files          19       19              
  Lines        1354     1350       -4     
  Branches      197      197              
==========================================
- Hits         1292     1290       -2     
+ Misses         22       20       -2     
  Partials       40       40              

Flag	Coverage Δ
py3.11	95.40% <100.00%> (?)
py3.12	95.40% <100.00%> (?)
py3.13	95.40% <100.00%> (?)
py3.14	95.38% <100.00%> (?)
py3.15	95.31% <100.00%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.