Django still stuck (Many to Many)

the idea is that students can send a ping to their teacher if they do not understand something, but first I am trying to get the student, teacher and whatever class they are in relationship so in my models after a few attempts I have come up with this

Models

from django.db import models

class Student(models.Model):
    name = models.CharField(max_length=50)


class Teacher(models.Model):
    name = models.CharField(max_length = 70)

class Lecture(models.Model):
    name = models.CharField(max_length = 70)
    members = models.ManyToManyField(
        Student,
        through = 'part_of_class',
        through_fields = ('lecture', 'student'),
    )
    lecturers = models.ManyToManyField(
        Teacher,
        through = 'Teacher_of_class',
        through_fields = ('lecture', 'teacher'),
    )

class Teacher_of_class(models.Model):
    lecture = models.ForeignKey(Lecture)
    teacher = models.ForeignKey(Teacher)

class part_of_class(models.Model):
    lecture = models.ForeignKey(Lecture)
    student = models.ForeignKey(Student)

Question is adding a student field messes up, and Im not even sure this is the right way, it sounds right in my head but I am sure I am missing something, any clues?