'Associate volume types to QoS.'

def handle_update(self, json_snippet, tmpl_diff, prop_diff):

    qos_specs = self.properties[self.QOS_SPECS]
    new_associate_vts = prop_diff.get(self.VOLUME_TYPES)
    old_associate_vts = self.properties[self.VOLUME_TYPES]
    (add_associate_vts, remove_associate_vts) = self._find_diff(new_associate_vts, old_associate_vts)
    for vt in add_associate_vts:
        self.client().qos_specs.associate(qos_specs, vt)
    for vt in remove_associate_vts:
        self.client().qos_specs.disassociate(qos_specs, vt)
