使用自定义管理器方法创建fixture，json转储以及避免类型错误的方法：xxx不是json可序列化的

I'm trying to create a test fixture using custom manager methods as my app uses a subset of dbtables and fewer records. so i dropped the idea of using initial_data. In manager I'm doing something like this. in Managers.py: I'm trying to create a test fixture using custo