House party rule: keep nice now and then (9)

I believe the answer is:

ravenclaw

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'house' is the definition.
I don't know anything about this answer so I cannot judge whether this works.

'party rule keep nice now and then' is the wordplay.
'party' becomes 'rave' (type of dance party).
'rule' becomes 'law' (law is a kind of rule).
'keep' indicates putting letters inside.
'now and then' means one should take alternating letters (letters taken on a regular basis, now and then).
The alternate letters of 'nice' are 'nc'.
'rave'+'law'='ravelaw'
'ravelaw' placed around 'nc' is 'RAVENCLAW'.

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I've seen this clue in the Sydney Morning Herald.

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