The previous version was

 N = a 'div' length xs
    where
        a = 10
      xs  = [1,2,3,4,5]

containing the following errors:

1. N is not allowed as function name (since it is uppercase).
2. the proper way of turning a function infix is `div` instead of 'div'
3. the second item of the where-group has to be indented exactly like the first one