Remove duplicates from a sorted linked list

Write a function that takes a list sorted in non-decreasing order and deletes any duplicate nodes from the list. The list should only be traversed once. 
For example if the linked list is 11->11->11->21->43->43->60 then removeDuplicates() should convert the list to 11->21->43->60.

Remove duplicates from a sorted linked list: https://www.geeksforgeeks.org/remove-duplicates-from-a-sorted-linked-list/