Set Sudoku

Here's a puzzle that came from the idea, "What if we just told them what the numbers were?"  No operations on the numbers in the cells, just an honest reveal of which numbers needed to be placed in groups of four cells, without saying which number goes in which cell exactly.  This is the result.  It's a sort of Set Sudoku.

This sort of puzzle doesn't have a very high difficulty cap, so this is definitely a break from some of the harder stuff posted here.  Still it's of interest for its contrast to other clue types which do something to the numbers rather than just give them away.

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Solution