How to use the transaction.get_transaction function in transaction

def __init__(self):
        # Upon first created instance, open the database:
        global _repositoryInitialized, _shared_state
        if not _repositoryInitialized:
            _shared_state = {}

            _storage = FileStorage('_Repository_')
            _db = db.DB(_storage)
            _connection = _db.open()
            _dbroot = _connection.root()

            if not _dbroot.has_key('thingList'):
                _dbroot['thingList'] = PersistentList()
            _shared_state['thingList'] = _dbroot['thingList']
            transaction.get_transaction().commit()

            _repositoryInitialized = True

        self.__dict__ = _shared_state

def commit(self):
        transaction.get_transaction().commit()

def save(self):
        transaction.get_transaction().commit()
        print 'Poing db saved'

def Commit(self):
        """ Commit all ZODB changes.
        """
        transaction.get_transaction().commit()

def commit(self):
        transaction.get_transaction().commit()
        print 'Poing db saved'

def commit(self):
        transaction.get_transaction().commit()
        print 'Poing db saved'

def abort(self):
        transaction.get_transaction().abort()

def abort(self):
        transaction.get_transaction().abort()