What to do with the error [<__main__.Student object at 0x000001E84D968090>, <__main__.Student object at 0x000001E84D95E750>]

Question

class Human:

    def __init__(self,name,surname,second_name):
        self.name = name
        self.surname = surname
        self.second_name = second_name

    def __str__(self):
        return "Ім'я = {}, Прізвище = {}, По батькові = {}".format(self.name,self.surname,self.second_name)

human_one = Human("Петро","Порошенко","Олексі́йович")
print(human_one)

class Student(Human):

    def __init__(self,name,surname,second_name, course, age):
        super().__init__(name,surname,second_name)
        self.course = course
        self.age = age

    def __str__(self):
        return("Student: [Ім'я = "+str(self.name)+ ", Прізвище = "+str(self.surname)+", По батькові = "+str(self.second_name)+", Курс = "+str(self.course)+", Роки життя = "+str(self.age),"]")

class Group:

    def __init__(self):
        self.list = []
        
    def add_messega(self,messega):
        return self.list.append(messega)

    def __str__(self):
        return str(self.list)
       
group_one = Group()

human_one = Student("Петро","Порошенко","Олексі́йович","4", "23")
human_two = Student("Алексій","Стерненко","Сергійович","2", "19")

group_one.add_messega(human_one)
group_one.add_messega(human_two)

print(group_one)

When I try to display the list of students, I get the following error