[Learn Python List Comprehension by Building a Case Converter Program - Step 5] f'string interpolation fails lesson but concatenation passes

[TracyChacon]

Describe the Issue

[Learn Python List Comprehension by Building a Case Converter Program - Step 5] f'string interpolation fails lesson but concatenation passes

• Only reproduced this issue in Chorme.130

Affected Page

https://www.freecodecamp.org/learn/scientific-computing-with-python/learn-list-comprehension-by-building-a-case-converter-program/step-5

Your code

if char.isupper():

            converted_character = f'_{char.lower()}'     # fails test
            converted_character = '_' + char.lower()    # passes test  

# Sorry, your code does not pass. Keep trying.

# You should assign the modified character to a variable named converted_character.![Image](https://github.com/user-attachments/assets/40669693-8e7b-4dc4-b2cf-3a4e499286d0)

Expected behavior

f'string should pass test

Screenshots

No response

System

• Device: Laptop
• OS: Windows 10
• Browser:Chrome
• Version: 130

Additional context

No response

[ilenia-magoni]

Right now the tests use a strict regex: https://github.com/freeCodeCamp/freeCodeCamp/blob/df4c4e3fd2419ff81ad903a9263599faedd27b6b/curriculum/challenges/english/07-scientific-computing-with-python/learn-list-comprehension-by-building-a-case-converter-program/657efa642593c5746acc5c81.md?plain=1#L18-L28

The test should be changed to use AST based helpers and accept both the concatenation and the f-string. Documentation on AST helpers can be found here: https://opensource.freecodecamp.org/curriculum-helpers/python.html#ast-based-helpers

The second test should also be updated to use AST based helpers: https://github.com/freeCodeCamp/freeCodeCamp/blob/df4c4e3fd2419ff81ad903a9263599faedd27b6b/curriculum/challenges/english/07-scientific-computing-with-python/learn-list-comprehension-by-building-a-case-converter-program/657efa642593c5746acc5c81.md?plain=1#L32-L40

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