Teachers sorting out the classrooms (13)

I believe the answer is:

schoolmasters

'teachers' is the definition.
(I know this)

'sorting out the classrooms' is the wordplay.
'sorting out' indicates anagramming the letters.
'the'+'classrooms'='theclassrooms'
'theclassrooms' is an anagram of 'SCHOOLMASTERS'.

I've seen this clue in The Guardian.

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