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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def find(self, start, end, limit=50, *args, **kwargs):
 """ find by creation date, using start and end dates as range """

        # check if spec has been specified, build on top of it
        fc = kwargs.get('spec', dict())

        # filter _id on start and end dates
        fc['_id'] = {'$gte': ObjectId.from_datetime(start),
                     '$lte': ObjectId.from_datetime(end)}

        if not self.collection:
            collection_name = kwargs.get('collection_name',
                             MONGODB_DEFAULT_COLLECTION)
            self.set_collection(collection_name)

        return self.collection.find(fc, limit=limit)