通过 ObjectId 在 mongodb 中使用 pymongo 进行搜索

我需要使用 pymongo 搜索带有 python 的 ObjectId，但是我总是得到这个错误。知道怎么搜索吗？

import pymongo
from pymongo import MongoClient
from pymongo import ObjectId


gate = collection.find({'_id': ObjectId(modem["dis_imei"])})
print gate


Traceback (most recent call last):
File "C:\Users\gerswin\Documents\Proyectos\Demonio py\test.py", line 2, in <module>
import pymongo
File "C:\Python27\lib\site-packages\pymongo\__init__.py", line 80, in <module>
from pymongo.connection import Connection
File "C:\Python27\lib\site-packages\pymongo\connection.py", line 39, in <module>
from pymongo.mongo_client import MongoClient
File "C:\Python27\lib\site-packages\pymongo\mongo_client.py", line 45, in <module>
from pymongo import (auth,
File "C:\Python27\lib\site-packages\pymongo\database.py", line 22, in <module>
from pymongo.collection import Collection
File "C:\Python27\lib\site-packages\pymongo\collection.py", line 25, in <module>
from pymongo.cursor import Cursor
File "C:\Python27\lib\site-packages\pymongo\cursor.py", line 19, in <module>
from bson import RE_TYPE
ImportError: cannot import name RE_TYPE