In the description for a triangle, a valid triangle is only valid if def isosceles(sides):
a b ≥ c
b c ≥ a
a c ≥ b
But you can pass the test without an equal sign. So for example a valid triangle that might fail without the equals is [2,2,4] of the isosceles function, or [1,3,4] for the scalene function.
Hi @TheKrol 
Welcome to the Exercism forums! Thanks for posting.
Trangles is a practice exercise that draws its problem description and test data from a common cross-track repository called problem specifications.
The exercise on the Python track is auto-generated from the problem specs repo. Suggestions for improving the exercise/test data, should be made under problem specifications, so that all tracks can benefit from the change.
@iHiD or @ErikSchierboom – could we move this to a more general discussion category?
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This has been discussed before. See the comments in https://github.com/exercism/problem-specifications/blob/main/exercises/triangle/canonical-data.json
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ah! Thank you for that!. I remembered a quite lengthy discussion, but couldn’t find it!
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