Bungling Boris maybe completely lost — it has been said before (9)

I believe the answer is:

iteration

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'it has been said before' is the definition.
(to iterate is to repeat an utterance)

I don't understand the rest of the clue.

(Other definitions for iteration that I've seen before include "Reprise" , "Repetition" , "Repeated performing" , "Repeats" , "Repeating" .)

I've seen this clue in The Guardian.

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