The function is given two strings t - template, s - to be sorted. Sort the characters in s such that if the character is present in t then it is sorted according to the order in t and other characters are sorted alphabetically after the ones found in t.
customSortt("edc", "abcdefzyx") ➞ "edcabfxyz"
customSortt("fby", "abcdefzyx") ➞ "fbyacdexz"
customSortt("", "abcdefzyx") ➞ "abcdefxyz"
customSortt("", "") ➞ ""
The characters in t and s are all lower-case.