bali-phy: Error! [1mMain.hs:10.1:[1;31m error:[0m[1m
   • pattern match failure in function
   [1;34m|[0m
[1;34m10[0m [1;34m| [0m[1;31mf[0m (Just x) = x
   [1;34m|[0m [1;31m^[0m

