extract unique values from list of strings

Certified Associate Developer

Hello, I have the following list of strings coming from a query: 

List of Text String - 4 items
"user1"(Text)
"user2"(Text)
"user2; user3"(Text)
"user4"(Text)

How  I can sort that so the final result will be list of strings of only unique values: 


Result:
"user1"(Text)
"user2"(Text)
"user3"(Text)
"user4"(Text)

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