def fetch_one(self, *args, **kwargs):
        bson_obj = self.fetch(*args, **kwargs)
        count = bson_obj.count()
        if count > 1:
            raise MultipleResultsFound("%s results found" % count)
        elif count == 1:
            return bson_obj.next()
return one document which match the structure of the object
dataset/ETHPy150Open namlook/mongokit/mongokit/document.py/Document.fetch_one