Part of Beatles song shows class (6)
I believe the answer is:
lesson
'class' is the definition.
(I've seen this before)
'part of beatles song shows' is the wordplay.
'part of' indicates the answer is hidden within the clue.
'LESSON' can be found hidden inside 'beatles song shows'.
(Other definitions for lesson that I've seen before include "Spell of instruction" , "School period" , "warning message" , "Sermon or class session" , "Portion of the scriptures read in church" .)