Returning black and white cab crosses street for class expert (10)

I believe the answer is:

taxonomist

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'class expert' is the definition.
The definition suggests a singular noun which matches the answer.

'returning black and white cab crosses street' is the wordplay.
'returning' is a reversal indicator.
'black and white' becomes 'mono' (I can't explain this - if you can you should believe this answer much more).
'cab' becomes 'taxi' (taxi cab).
'crosses' is an insertion indicator.
'street' becomes 'st' (abbreviation).
'mono' in reverse letter order is 'onom'.
'onom' going into 'taxi' is 'taxonomi'.
'taxonomi'+'st'='TAXONOMIST'

'for' acts as a link.

Can you help me to learn more?

(Other definitions for taxonomist that I've seen before include "Classifier of organisms" , "one analysing the class system?" .)

I've seen this clue in The Times.

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