python bfils.erreurs.InvalidDocument: Ne peut pas encoder objet: datetime.date(2015, 3, 1)

J'ai les fonctions suivantes:

#  this is in a module called 'dbw_lib'
def dateTimeOuput(start_days_back, end_days_back):
    start_delta = datetime.timedelta(days=start_days_back)
    end_delta = datetime.timedelta(days=end_days_back)
    start_date = datetime.date.today() - start_delta
    end_date = datetime.date.today() - end_delta
    return start_date, end_date

def dictByDate(start_days, end_days):
    start_date, end_date = dbw_lib.dateTimeOuput(start_days, end_days)

    date_string = { "created_at": {"$gte" : start_date, "$lt": end_date }  }

    user_id_email_dict = dbw_lib.dbwIdToEmailD(user_coll_obj, date_query = date_string)  # dict of all user ids and emails  
    print user_id_email_dict
    quit()

quand je lance key_dicts = dictByDate(90, 60), j'ai la suite de l'exī:

Traceback (most recent call last):
File "main.py", line 212, in <module>
program.runProgram()
File "main.py", line 61, in runProgram
report.RcreateReport()
File "filepath/report.py", line 86, in RcreateReport
key_dicts = dictByDate(90, 60)
File "filepath/report.py", line 65, in dictByDate
user_id_email_dict = dbw_lib.dbwIdToEmailD(user_coll_obj, date_query = date_string)  # dict of all user ids and emails  
File "filepath/dbw_lib.py", line 50, in dbwIdToEmailD
for pair in id_email_cursor:
File "/Library/Python/2.7/site-packages/pymongo-3.0-py2.7-macosx-10.9-intel.egg/pymongo/cursor.py", line 968, in __next__
File "/Library/Python/2.7/site-packages/pymongo-3.0-py2.7-macosx-10.9-intel.egg/pymongo/cursor.py", line 905, in _refresh
File "/Library/Python/2.7/site-packages/pymongo-3.0-py2.7-macosx-10.9-intel.egg/pymongo/cursor.py", line 812, in __send_message
File "/Library/Python/2.7/site-packages/pymongo-3.0-py2.7-macosx-10.9-intel.egg/pymongo/mongo_client.py", line 732, in _send_message_with_response
File "/Library/Python/2.7/site-packages/pymongo-3.0-py2.7-macosx-10.9-intel.egg/pymongo/mongo_client.py", line 743, in _reset_on_error
File "/Library/Python/2.7/site-packages/pymongo-3.0-py2.7-macosx-10.9-intel.egg/pymongo/server.py", line 85, in send_message_with_response
File "/Library/Python/2.7/site-packages/pymongo-3.0-py2.7-macosx-10.9-intel.egg/pymongo/message.py", line 107, in get_message
bson.errors.InvalidDocument: Cannot encode object: datetime.date(2015, 3, 1)

OriginalL'auteur dwstein | 2015-05-31