from datetime import datetime

class Product():
    def __init__(self, cost, name, date):
        self.cost = cost
        self.name = name
        self.date = date

    def days_left(self):
        return datetime.now() - self.date

@@ -157,16 +157,51 @@
 e = date
+%0A        self.passed_phases = set()
 %0A%0A    de
@@ -257,12 +257,66 @@
 - self.date%0A
+%0A%0Aif __name__ == '__main__':%0A    main()%0A%0A%0Adef main():%0A

Add passed_phases to Product and create main function