Different version of same old ideas about cannabis (6)

I believe the answer is:

rehash

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'different version of same old ideas' is the definition.
I can't tell whether this defines the answer.

'about cannabis' is the wordplay.
'about' becomes 're' ('re' means regarding or about).
'cannabis' becomes 'hash' (hash is a kind of cannabis).
're'+'hash'='REHASH'

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(Other definitions for rehash that I've seen before include "Rework old material" , "new disposition" , "Re-use old material with little or no change" , "Serve up old ideas" , "Reworking of old material" .)

I've seen this clue in The Irish Times.

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