Each class function (7)
I believe the answer is:
perform
'function' is the definition.
(I've seen this before)
'each class' is the wordplay.
'each' becomes 'per' ('per' can mean for each).
'class' becomes 'form' (synonyms).
'per'+'form'='PERFORM'
(Other definitions for perform that I've seen before include "Carry out (action)" , "act on stage" , "Act in play or film" , "Carry out, accomplish" , "Carry out (a task)" .)