One wouldn't spend a day teaching here (7,6)

I believe the answer is:

evening school

'one wouldn't spend a' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.

'day teaching here' is the wordplay.
'day' becomes 'evening' (evening is a kind of day).
'teaching here' becomes 'school' (I can't explain this - if you can you should believe this answer much more).
'evening'+'school'='EVENING SCHOOL'

I've seen this clue in The Guardian.

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