 
 <prompt> ```python
# Code remains the same
A company sell 4000 gallons of milk for jar to Mr. Marcellus' store at the cost of $3.5 per gallon. But, Mr. Marcellus later come sabi say 2/5 of the amount of milk wey he buy don expire and e no fit sell am again. He carry the sour milk go back give the company and order for refund. Calculate how much he collect as refund. Abeg, use python!
``` <response>: ```
def solution():
    """One company sell 4000 gallons of milk for jar to Mr. Marcellus' store at the cost of $3.5 per gallon. But, Mr. Marcellus later come sabi say 2/5 of the milk wey he buy don expire and e no fit sell am. He carry the sour milk go back give the company and say make dem give am him money back. Calculate how much he collect as refund."""
    milk_initial = 4000
    milk_expired = milk_initial * 2 / 5
    milk_cost = 3.5
    refund = milk_expired * milk_cost
    result = refund
    return result
``` 