Environment

Cascadia Code version number: GitHub master branch
Application (with version) used to display text:
OS platform and version:
Screen resolution (i.e. 220dpi): 

Any other software?

Steps to reproduce

https://github.com/microsoft/cascadia-code/search?q=step_remove_ligatures

flake8 testing of https://github.com/microsoft/cascadia-code on Python 3.8.3

$ flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics

./build.py:258:25: F821 undefined name 'step_remove_ligatures'
                        step_remove_ligatures,
                        ^
./build.py:303:17: F821 undefined name 'step_remove_ligatures'
                step_remove_ligatures,
                ^
2     F821 undefined name 'step_remove_ligatures'
2

https://flake8.pycqa.org/en/latest/user/error-codes.html

On the flake8 test selection, this issue does not focus on "style violations" (the majority of flake8 error codes that psf/black can autocorrect). Instead these tests are focus on runtime safety and correctness:

• F82 tests are undefined names which are usually a sign of a typo, missing imports, or code that has not been ported to Python 3. These also would be compile-time errors in a compiled language but in Python a NameError is raised which will halt/crash the script on the user.

Expected behavior

Actual behavior