Django使用.set添加多个与m2m相关的模型记录很好，但是如何添加ids以外的其他模型字段呢？

from django.db import models

class ModelA(models.Model):
    # 模型A的字段

class ModelB(models.Model):
    # 模型B的字段
    extra_field = models.CharField(max_length=100)
    a = models.ManyToManyField(ModelA)

class ModelB(models.Model):
    # 模型B的字段
    extra_field = models.CharField(max_length=100)
    a = models.ManyToManyField(ModelA, through='ModelC')

class ModelC(models.Model):
    a = models.ForeignKey(ModelA, on_delete=models.CASCADE)
    b = models.ForeignKey(ModelB, on_delete=models.CASCADE)
    extra_field = models.CharField(max_length=100)

model_a_instance = ModelA.objects.get(id=1)
model_b_instance = ModelB.objects.get(id=1)

model_c_instance = ModelC.objects.create(a=model_a_instance, b=model_b_instance, extra_field='Some value')

model_b_instance.a.add(model_c_instance)