Identify the bug in this Expense class method that calculates each user's share:

Identify the bug in this Expense class method that calculates each user's share:

class Expense:
    def __init__(self, amount, paid_by, split_between):
        self.amount = amount
        self.paid_by = paid_by
        self.split_between = split_between

    def split_amount(self):
        return self.amount // len(self.split_between)