replace set by frozenset

[felipeZ]

No description provided.

[codecov]

Codecov Report

Merging #47 (9d85ba3) into master (1aa8dcc) will decrease coverage by 1.80%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #47      +/-   ##
==========================================
- Coverage   90.27%   88.46%   -1.81%     
==========================================
  Files          11       11              
  Lines         555      555              
  Branches       57       57              
==========================================
- Hits          501      491      -10     
- Misses         39       45       +6     
- Partials       15       19       +4     

Impacted Files	Coverage Δ
flamingo/screen.py	79.73% <100.00%> (-6.54%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 1aa8dcc...9d85ba3. Read the comment docs.