quickCheckResult only accept `something -> Bool`, then i mimic some example, 
pass 

```
[Colour] -> Bool

```

what is function of the bracket of [Colour]? why not `Colour -> Bool`?
How to pass Arbitrary instance to quickCheckResult?

```
data Colour = Green | Blue
instance Arbitrary Colour where
   arbitrary = oneof [return Green, return Blue]

main = quickCheckResult ((\s -> s == s) :: [Colour] -> Bool)

```

[Updated]
My goal is the following can run

```
import Test.QuickCheck.Function
import Test.QuickCheck.Gen
import Test.QuickCheck
import Test.QuickCheck.Function
import Test.QuickCheck.Arbitrary
import Test.QuickCheck.Property
import Test.QuickCheck.Test

prop1 f g x = (g.f) x == (f.g) x where types = [f, g] :: [Int->Int]

instance CoArbitrary ex where
  coarbitrary f g = prop1 (variant 0 f) (variant 0 g)

main = quickCheck prop1

test5.hs:11:10:
    Illegal instance declaration for `CoArbitrary ex'
      (All instance types must be of the form (T a1 ... an)
       where a1 ... an are *distinct type variables*,
       and each type variable appears at most once in the instance head.
       Use -XFlexibleInstances if you want to disable this.)
    In the instance declaration for `CoArbitrary ex'

```

3.How to use QuickCheck.Function (Updated)

```
prop :: Fun Fun Integer -> Bool
let prop (Fun _ f) (Fun _ g) = (g.f) x == (f.g) x
quickCheck prop

```

parse error (possibly incorrect indentation)