In this task, you are given a string of characters. You need to remove duplicate characters from the string if any, and return the resulting string.

[EX Q]: cwBQvgwEkNhVLIoizKkgpaphR
[EX A]: cwBQvgEkNhVLIoizKpaR

[EX Q]: CLyrpjdLVkXMJMuYNzraRAtyRcH
[EX A]: CLyrpjdVkXMJuYNzaRAtcH

[EX Q]: wghwXLflnbkSbtCbFosA
[EX A]:
wghXLflnbkStCFosA