Python pattern design implementation

So, I have some student class that calculate grades with 40% from exams and 60%. And need to use some design pattern that allows me to use different calculate to calculate with ratio 45% and 55% without changing student class. And in main I have to print score with using calculate 1, then other calculate 2, and then back to calculate one. I believe it might be either Factory Pattern, or adapter pattern but I do not know how to implement them.

class Student(Calculate):
    def __init__(self, studentName):
        self.__studentName = studentName
        self.__homeworks = []
        self.__exams = []

    @property
    def studentName(self):
        return self.__studentName

    @property
    def homeworks(self):
        return self.__homeworks

    @property
    def exams(self):
        return self.__exams

    @studentName.setter
    def studentName(self, studentName):
        self.__studentName = studentName

    def addHWScore(self, score):
        self.__homeworks.append(score)

    def addExamScore(self, score):
        self.__exams.append(score)

    def calculate(self):
        sum1 = 0
        sum2 = 0
        for x in self.__homeworks:
            sum1 = sum1 + x

        for y in self.__exams:
            sum2 = sum2 + y

        avg = ((sum1 / len(self.__homeworks)) * 0.4 + (sum2 / len(self.__exams)) * 0.6)
        return 'Student: ' + self.__studentName + ', avarage grade: ' + str(avg)


def main():
    student1 = Student('John')
    student1.addExamScore(100)
    student1.addHWScore(80)

    student2 = Student('Alex')
    student2.addExamScore(90)
    student2.addExamScore(95)
    student2.addHWScore(85)
    student2.addHWScore(85)

    print('calculate 1')
    print('===========')
    print(student1.calculate())
    print(student2.calculate())
    print()

    print('calculate 2')
    print('===========')
    ???

    print()
    print('calculate 1')
    print('===========')

    print(student1.calculate())
    print(student2.calculate())

 


main()

I need to somehow to be able put this calculate on calculate 2, and switch back

def calculate(self):
        sum1 = 0
        sum2 = 0
        for x in self.__homeworks:
            sum1 = sum1 + x

        for y in self.__exams:
            sum2 = sum2 + y

        avg = ((sum1 / len(self.__homeworks)) * 0.45 + (sum2 / len(self.__exams)) * 0.55)
        return 'Student: ' + self.__studentName + ', avarage grade: ' + str(avg)