Extend time in prison (7)

I believe the answer is:

stretch

I believe this clue is a double definition.

'extend' is the first definition.
(synonyms)

'time in prison' is the second definition.
(I've seen this before)

(Other definitions for stretch that I've seen before include "Exaggerate" , "Do warm-up exercises" , "What one does in prison" , "Draw out" , "Exercise - period" .)

I've seen this clue in The Times.

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