我无法在Django ManyToMany Relation中获取字段

我的Django模型中有一个称为“公告”的模型，它的工作方式是它有一个消息字段，我可以键入消息的主体以及作为消息接收者的student_id。我正在使用student_id上的多对多字段，以便能够将消息发送给某个特定学生，然后在其前端过滤特定学生的消息，但是当我尝试过滤特定学生时，我在发送邮件时选择了它，它根本不显示任何信息。

models.py

class Announcement_by_dean(models.Model):
    student_id = models.ManyToManyField(add_students_by_manager)
    message = models.TextField()
    sent_date = models.DateField(default=datetime.now(), blank=True)
    updated_date = models.DateField(auto_now=True, blank=True)

    def __str__(self):
        return "message sent on "+ str(self.sent_date)

class add_students_by_manager(models.Model):
    manager_ID = models.ForeignKey(Manager_login_information, on_delete=models.CASCADE)
    student_ID = models.CharField(max_length=200)
    student_name = models.CharField(max_length=200)
    phone_number = models.CharField(max_length=200)
    address = models.CharField(max_length=200)
    dob = models.CharField(max_length=200)
    major = models.CharField(max_length=200)
    password = models.CharField(max_length=200)

    def __str__(self):
        return self.student_name

views.py

def dean_page(request):
    annoucement_list = Announcement_by_dean.objects.all().order_by('-id')
    return render(request, 'dean_page.html', context)

dean_page.html

<div class="tab-pane fade show" id="nav-announcement-list" role="tabpanel" aria-labelledby="nav-announcement-list-tab">
  {% if annoucement_list %}
  {% for k in annoucement_list %}
  <div class="card container mt-4 mb-5">
    <div class="card-body">
      Messsage: {{k.message}}<br>
      Sent to: {{k.student_id.student_ID}}<br>
    </div>
  </div>
  {% endfor %}
  {% else %}
  <div class="mt-4 ml-5 pl-5">
    <span class="text-muted container pt-5 pl-5 ml-5">No Annoucement(s) has been made</span>
  </div>
  {% endif %}
</div>