Please answer in SML$/$ML$!$ Also use map, foldl, or foldr functions and$/$or case expressions. Thank you!

Write a function convert of type $(\text{'}$a $*\text{'}$b$)$ list $->$ 'a list $*\text{'}$b list, that converts a list of pairs into a pair of lists, preserving the order of the elements. For example, convert $[(1,2),(3,4),(5,6)]$ should evaluate to $([1,3,5),(2,4,6]).$