did your test pass for the list having only 1 string element? mine isn't goin. it's the fourth one when you go to attempt

test.assert_equals(filter_list([1,2,'aasf','1','123',123]) - in this list one of the digits "1" - is a string, not a number. So it doesn't show in results ([1,2,123]) not because it is a duplicate, but because it's a string. So you should check in your code if you have any "string" numbers and exclude them too.
You are welcome)

same issue as well