Feeling of pleasure in key agreement (13)

I believe the answer is:

gratification

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'feeling of pleasure' is the definition.
(feeling gratified or pleased)

'in key agreement' is the wordplay.
'in key' becomes 'g' (musical key. I am not sure about the 'in' bit.).
'agreement' becomes 'ratification' (ratification is a kind of agreement).
'g'+'ratification'='GRATIFICATION'

Can you help me to learn more?

(Other definitions for gratification that I've seen before include "giving pleasure" , "Delight" , "Source of pleasure" , "Feeling of satisfaction" .)

I've seen this clue in The Times.

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