Cartesian product Exercise that I can't seem to get to compile on Purescript

CartesianProductExercise.md

Here's the code as part of a coding exercise (the 2nd one) here:

module CartesianProductExercise where
  
import Prelude

import Data.Tuple (Tuple(..))

cartesianProduct :: ∀ a b. Array a -> Array b -> Array (Tuple a b)
cartesianProduct left right = do
  a_ <- left
  b_ <- right
  pure[ Tuple a_ b_ ]

The error that spago returns is:

Compiling CartesianProductExercise
Error found:
in module CartesianProductExercise
at src/CartesianProductExercise.purs:9:3 - 9:13 (line 9, column 3 - line 9, column 13)

  Could not match type
         
    Array
         
  with type
            
    Tuple a0
            

while trying to match type Array (Tuple a0 b1)
  with type Tuple a0 b1
while checking that expression (bind left) (\a_ ->                 
                                              (bind right) (\b_ -> 
                                                              ...  
                                                           )       
                                           )                       
  has type Array (Tuple a0 b1)
in value declaration cartesianProduct

where b1 is a rigid type variable
        bound at (line 0, column 0 - line 0, column 0)
      a0 is a rigid type variable
        bound at (line 0, column 0 - line 0, column 0)

See https://github.com/purescript/documentation/blob/master/errors/TypesDoNotUnify.md for more information,
or to contribute content related to this error.


[error] Failed to build.

What I'm trying to do is specify a Tuple so that I can match the types of the two arrays.

Can anyone help?