设计一个成绩证书生成系统的api，具体实现代码

设计一个成绩证书生成系统API，通常会包含以下几个关键部分：

1. **数据模型** (Model):

class Student:
    def __init__(self, id, name, grades):
        self.id = id
        self.name = name
        self.grades = grades

class Certificate:
    def __init__(self, student, course_name, grade):
        self.student = student
        self.course_name = course_name
        self.grade = grade

2. **接口定义** (Interface):

from abc import ABC, abstractmethod

class CertificateGenerator(ABC):
    @abstractmethod
    def generate_certificate(self, student: Student, course: str) -> str:
        pass

3. **具体实现** (Concrete Implementation):

class PDFCertificateGenerator(CertificateGenerator):
    def generate_certificate(self, student: Student, course: str) -> str:
        # 使用学生信息和课程名称生成PDF证书内容
        certificate_content = f"学生ID: {student.id}\n姓名: {student.name}\n课程: {course}\n成绩: {student.grades[course]}"
        return certificate_content

4. **服务端函数** (Server Function):

def create_certificates(student: dict, courses: list) -> None:
    student_obj = Student(**student)
    generator = PDFCertificateGenerator()

    for course in courses:
        if course in student_obj.grades:
            certificate_str = generator.generate_certificate(student_obj, course)
            # 打印或保存到文件
            print(f"证书已生成: {certificate_str}")

5. **调用示例**:

student_data = {"id": "001", "name": "张三", "grades": {"数学": 95, "英语": 88}}
courses = ["数学", "英语"]
create_certificates(student_data, courses)