对于生成的id，直接用str()即可转为字符串，而对于字符串，使用bson.objectid.ObjectId将字符串转为ObjectId类型

示例代码

from bson.objectid import ObjectId

str_id = "62ef8ac55e820c5d091e7380"

object_id = ObjectId(str_id)  # 字符串转ObjectID
print(object_id, type(object_id))

string_id = str(object_id)  # ObjectID转字符串
print(string_id, type(string_id))

得到结果：

62ef8ac55e820c5d091e7380 <class 'bson.objectid.ObjectId'>
62ef8ac55e820c5d091e7380 <class 'str'>