redundant subtransaction section

[qyq]

In neutron_taas/services/taas/taas_plugin.py, every plugin method such as create_tap_service has a redundancy subtransaction section ,eg:
In neutron_taas/services/taas/taas_plugin.py,

......
89 with context.session.begin(subtransactions=True):
90 ts = super(TaasPlugin, self).create_tap_service(context,
91 tap_service)
92 driver_context = sd_context.TapServiceContext(self, context, ts)
93 self.driver.create_tap_service_precommit(driver_context)
......
in line 89:I think "with context.session.begin(subtransactions=True):" is redundant, for in taas_db.create_tap_service and create_tap_service_precommit there exists "with context.session.begin(subtransactions=True):" section.
I wonder whether every such plugin method should delete the section.

[YAMAMOTO Takashi (yamamoto)]

maybe we can remove the one in taas_db.