None here is sane (3,5)

I believe the answer is:

all there

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'sane' is the definition.
(I've seen this before)

I don't understand how the remainder of the clue works.

(Other definitions for all there that I've seen before include "The gate" , "sensible" , "Total number of people attending" , "Sane - none missing?" , "quite astute" .)

I've seen this clue in The Globe and Mail.

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