Polish collection (5)

I believe the answer is:

class

I believe this is a double definition.

'polish' is the first definition.
(I've seen this in another clue)

'collection' is the second definition.
(I know that class is a type of collection)

(Other definitions for class that I've seen before include "Taste or style" , "Category; lesson" , "sophistication" , "Stylish; lesson" , "High quality" .)

I've seen this clue in The Guardian.

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