class to calculate gpa based on weighted value from credits and marks from user input

class GPA:
    def __init__(self):
        self.credits = []
        self.grades = []

    def addCourse(self, grade, credit):
        self.credits.append(credit)
        self.grades.append(grade)

    def calcGpa(self):
        total_credits = 0
        grade_point = 0
        for i in range(len(self.credits)):
            grade_point += self.grades[i] * self.credits[i]
            total_credits += self.credits[i]
        return grade_point / total_credits