OCAML PROGRAMMING LANGUAGE ONLY

Write a recursive function called partition that takes a pivot item and a list as arguments, and returns a tuple containing a list of items from the list that are less than the pivot and a list of items from the list that are greater than or equal to the pivot. If the original list contains duplicate items then the partitions should also contain duplicate items. If the original list is empty, both of the partitions should be empty. You may not use any built-in list functions.