Programmer Humor

It's obviously:

Traceback (most recent call last): File "./main.py", line 2, in AttributeError: 'str' object has no attribute 'length'

The answer is 6. It's 6 characters long.

Are they using a red pen to write the checkmarks for correct answers to make it confusing but logical at least?

Good thing this only uses ASCii characters, else you get into some fun discussions about UTF encoding

They missed out the context code:

trait DoW { def length: FiniteDuration }
object Monday extends DoW { override def length = 24.hours }
...
implicit def toDoW(s: String): DoW = s match {
 case "Monday" => Monday
...
}
var day: DoW = _

(Duration formatting and language identification are left as an exercise for the reader)

The future is not yet young man.

For 1 hour = 4^(-1) characters

hours = 0.25

There. I fixed it! :)