Python ascending$\_$pairs

Define a function named ascending$\_$pairs that takes one parameter of type list$[$list$[$int$]].$

This function must return a new list with elements $($the nested lists$)$ matching those of the input list $($in the same order$)$ but such that any nested list of length $2$ in the result has its elements in ascending order $($really$,$ non$-$descending; i$.$e$.,$ the first element will be less than or equal to the second$).$ The elements of nested lists of length not equal to $2$ must remain in the same order as in

the input.