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]: wghwXLflnbkSbtCbFosA
[EX A]: wghXLflnbkStCFosA

[EX Q]: kjynMHqaVPzfJDTnXNHz
[EX A]: kjynMHqaVPzfJDTXN

[EX Q]: vbzTYPGtcLOutwmpcLPOyjppQI
[EX A]:
vbzTYPGtcLOuwmpyjQI