Hi.
I'm surprised by these two test cases that seem to contradict each other:
fn x => 0 must raise an error according to the button test,
fn one => 1 must be a valid function with no arguments and always return 1 according to the attempt.

In my opinion the first test case means 'a function must have a name' but in that case x could be considered to be the name of a function..

Should the test case be modified?
How did you managed this?