几周来，我一直在尝试循环处理来自json序列化程序的传入数据，尝试了几种不同的方法，但是我似乎不能循环遍历json并返回一个包含所有facility_id的列表。最终我想为每个json项创建一个leadfacility对象，使用它的facility_id和它的datetime。但是我似乎甚至不能访问facility_ID。正在分配的设施已在数据库中。
有人知道我在这里遗漏了什么吗？我如何循环通过“assigned_facilities”？我唯一能返回的是用print（）一次返回整个json数据。或者我的json数据结构不正确？

class LeadUpdateSerializer(serializers.ModelSerializer):
    assigned_facilities = serializers.JSONField(required=False, allow_null=True, write_only=True)

    def create(self, validated_data):
        
        assigned_facilities = validated_data.pop("assigned_facilities")
        instance = Lead.objects.create(**validated_data)

        for item in assigned_facilities:
            instance.leadfacility.create(assigned_facilities_id=assigned_facilities.get('facility_id'), datetime=assigned_facilities.get('datetime'))
            
        return instance

Json

{
    "assigned_facilities": [{
            "facility_id": "1",
            "datetime": "2018-12-19 09:26:03.478039"
        },
        {
            "facility_id": "1",
            "datetime": "2019-12-19 08:26:03.478039"
        }
    ]
}

models.py

class LeadFacilityAssign(models.Model):
    assigned_facilities = models.ForeignKey(Facility, on_delete=models.CASCADE, related_name='leadfacility')
    lead = models.ForeignKey(Lead, on_delete=models.CASCADE, related_name='leadfacility')
    datetime = models.DateTimeField(null=True, blank=True)

class Facility(models.Model):
    name = models.CharField(max_length=150, null=True, blank=False)

    def __str__(self):
        return self.name

class Lead(models.Model):
    first_name = models.CharField(max_length=40, null=True, blank=True)
    last_name = models.CharField(max_length=40, null=True, blank=True)

    def __str__(self):
        return f"{self.first_name} {self.last_name}"