def connect(self): 
        try:
            self.connection = pymongo.Connection(self.host, self.port)
            self.db = self.connection[self.name]
        except AutoReconnect:
            raise DatabaseException("It's not possible connect to the database")
def _raise_or_warn(self, warn_only, msg):
        if warn_only:
            self._warnings.append(msg)
        else:
            raise TransactionError(msg)