Solution: The Single Responsibility Principle

from data import students_data
from classes import Student, SemesterResult, CGPACalculator
if __name__ == "__main__":
    # Creating a list of students using students_data
    students = []
    for student_item in students_data:
        # Creating a student instance
        student = Student(student_item['ID'], student_item['name'], student_item['major'])
        # Appending student results
        for result_item in student_item['results']:
            # Creating a result instance and adding to student's results
            result = SemesterResult(result_item['number'], result_item['gpa'], result_item['ch'])
            student.add_semester_result(result)
        students.append(student)
    # Calculating students' CGPAs
    for student in students:
        print(
            f"student ID: {student.get_id()},",
            "CGPA: %0.2f" % (CGPACalculator.calculate(student.get_results()))
        )