Marked Lists

You are given two lists of strings list1 and list2, which are sorted alphabetically in ascending order.

Implement a function that merges these two lists into one sorted list marking all items from list1 and list2 with characters $"1"$ and $"2"$ respectively at the end of each item and return that list.

Example:

Input:

list1 = ["ball","ninja","plan"]
list2 = ["cat","egg","zoo"]

Output:

def mark_lists(list1,list2) ->
["ball1","cat2","egg2","ninja1","plan1","zoo2"]