about alarm update with --query

Hi all,

I use aodh cli to create a event alarm with query condition, the cli runs successfully.
But when i want to update the query condition, the cli runs failed.
The help info about `--query` para with these two cli have no difference.
The information is as follows, Does anyone else know why? Thanks~

stack@cloud:~$ aodh alarm create --name test --type event --event-type compute.instance.update --query "traits.instance_id=string::3ed4fbc1-023e-4c4e-85d3-cf6d73c9ac49"

+---------------------------+-----------------------------------------------------------+
| Field | Value |
+---------------------------+-----------------------------------------------------------+
| alarm_actions | [] |
| alarm_id | 8d1018bd-8f14-4f34-b47c-54588488d658 |
| description | Alarm when compute.instance.update event occurred. |
| enabled | True |
| event_type | compute.instance.update |
| insufficient_data_actions | [] |
| name | test |
| ok_actions | [] |
| project_id | f0895991f44044ccba8e62b201b70360 |
| query | traits.instance_id = 3ed4fbc1-023e-4c4e-85d3-cf6d73c9ac49 |
| repeat_actions | False |
| severity | low |
| state | insufficient data |
| state_timestamp | 2016-11-29T06:31:50.094836 |
| time_constraints | [] |
| timestamp | 2016-11-29T06:31:50.094836 |
| type | event |
| user_id | 7d7531a2030d4537b60a5193bf6ab286 |
+---------------------------+-----------------------------------------------------------+
stack@cloud:~$
stack@cloud:~$
stack@cloud:~$ aodh alarm update 8d1018bd-8f14-4f34-b47c-54588488d658 --event-type computer.instance.delete --query "traits.instance_id=string::3ed4fbc1-023e-4c4e-85d3-cf6d73c9ac88"

Invalid input for field/attribute data. Value: '{'alarm_actions': [], 'event_rule': {'query': 'traits.instance_id=string::3ed4fbc1-023e-4c4e-85d3-cf6d73c9ac88', 'event_type': 'computer.instance.delete'}, 'ok_actions': [], 'name': 'test', 'state': 'insufficient data', 'timestamp': '2016-11-29T06:31:50.094836', 'enabled': True, 'state_timestamp': '2016-11-29T06:31:50.094836', 'severity': 'low', 'alarm_id': '8d1018bd-8f14-4f34-b47c-54588488d658', 'time_constraints': [], 'insufficient_data_actions': [], 'repeat_actions': False, 'user_id': '7d7531a2030d4537b60a5193bf6ab286', 'project_id': 'f0895991f44044ccba8e62b201b70360', 'type': 'event', 'description': 'Alarm when compute.instance.update event occurred.'}'. Value not a valid list: traits.instance_id=string::3ed4fbc1-023e-4c4e-85d3-cf6d73c9ac88 (HTTP 400) (Request-ID: req-ad8bd440-2784-43b7-98d7-7e0ae27dcebc)
stack@cloud:~$