class Student(Person):

    #   Class Constructor
    #
    #   Parameters:
    #   firstName - A string denoting the Person's first name.
    #   lastName - A string denoting the Person's last name.
    #   id - An integer denoting the Person's ID number.
    #   scores - An array of integers denoting the Person's test scores.
    #
    # Write your constructor here
    def __init__(self, _firstName, _lastName, _id, _scores):
        Person.__init__(self, _firstName, _lastName, _id)
        self.scores = _scores
    #   Function Name: calculate
    #   Return: A character denoting the grade.
    #
    # Write your function here
    def calculate(self):
        average = sum(self.scores) / len(self.scores)
        if 90 <= average <= 100:
            grade = "O"
        elif 80 <= average < 90:
            grade = "E"
        elif 70 <= average < 80:
            grade = "A"
        elif 55 <= average < 70:
            grade = "P"
        elif 40 <= average < 55:
            grade = "D"
        else:
            grade = "T"
        return grade

foo(?=bar)
# 직후에 bar가 있는 foo에 일치한다.

foo(?!bar)
# 직후에 bar가 없는 foo에 일치한다.