関数takeを作りたいのですが、うまくいきません。
myTake :: Int -> [a] -> [a]
myTake num (x:xs)
| num < 0 = error"Not Valid"
| num == 0 = []　-- Non-Exhastiveになる　myTake 0 []
| num == 1 = [x]
| num > 0 = [x] ++ myTake (num -1) (xs)
| otherwise = error"Not Valid"
myTake 2 [] -> Non-Exhastive