python利用类方法，编写学生成绩管理系统。定义学生类，包含学号、姓名、英语成绩、python成绩、java成绩、c语言成绩、总成绩。系统有增删查改功能。

好的，我可以为您提供一个简单的学生成绩管理系统的代码示例。代码如下：

class Student:
    # 学生类
    def __init__(self, id, name, english_score, python_score, java_score, c_score):
        self.id = id
        self.name = name
        self.english_score = english_score
        self.python_score = python_score
        self.java_score = java_score
        self.c_score = c_score
        self.total_score = english_score + python_score + java_score + c_score

    def __str__(self):
        return f'{self.id} {self.name} {self.english_score} {self.python_score} {self.java_score} {self.c_score} {self.total_score}'

class StudentManager:
    # 学生成绩管理类
    students = []
    @classmethod
    def add_student(cls, student):
        cls.students.append(student)

    @classmethod
    def remove_student(cls, id):
        for student in cls.students:
            if student.id == id:
                cls.students.remove(student)
                return

    @classmethod
    def query_student(cls, id):
        for student in cls.students:
            if student.id == id:
                return student

    @classmethod
    def modify_student(cls, id, name, english_score, python_score, java_score, c_score):
        for student in cls.students:
            if student.id == id:
                student.name = name
                student.english_score = english_score
                student.python_score = python_score
                student.java_score = java_score
                student.c_score = c_score
                student.total_score = english_score + python_score + java_score + c_score
                return

    @classmethod
    def get_all_students(cls):
        return cls.students

# 测试
if __name__ == '__main__':
    # 添加学生
    StudentManager.add_student(Student('001', '张三', 80, 90, 85, 95))
    StudentManager.add_student(Student('002', '李四', 75, 85, 90, 92))
    StudentManager.add_student(Student('003', '王五', 90, 80, 95, 85))
    # 查询学生
    student = StudentManager.query_student('001')
    print(student)
    # 修改学生
    StudentManager.modify_student('001', '张三丰', 85, 95, 90, 80)
    student = StudentManager.query_student('001')
    print(student)
    # 删除学生
    StudentManager.remove_student('002')
    students = StudentManager.get_all_students()
    for student in students:
        print(student)

上述代码中，定义了一个学生类和一个学生成绩管理类。学生类包含了学号、姓名、英语成绩、Python成绩、Java成绩、C语言成绩和总成绩属性，以及初始化方法和字符串表示方法。学生成绩管理类包括了增加学生、删除学生、查询学生、修改学生和获取所有学生的方法，都是类方法。在测试部分中，我们演示了如何使用这个学生成绩管理系统。