'Helper method for checking vlan transparecncy support.
:param context: context parameter to pass to each method call
:raises: neutron.extensions.vlantransparent.
VlanTransparencyDriverError if any mechanism driver doesn\'t
support vlan transparency.'

def _check_vlan_transparency(self, context):

    if context.current.get('vlan_transparent'):
        for driver in self.ordered_mech_drivers:
            if (not driver.obj.check_vlan_transparency(context)):
                raise vlantransparent.VlanTransparencyDriverError()
