Business hours function in Postgres

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$30 - $250

Project Description:
I need a function for Postgres which works in Postres 8 and above which will take 2 timestamp parameters and give me the difference in business hours.
There will be multiple other tables for holidays, working hours for each day etc but in the end, the function will return me two numbers for hours and minutes which are the working hours and minutes between 2 timestamps.

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