Search fails if response from API service contains additional keys

Response from API search entry point can contains additional keys in data list elements (which are not hardcoded in the client).
Search fails with exeption from the client for this case.
Example for ironic plugin (under development):

run(Namespace(all_projects=False, columns=[], formatter='table', json=True, max_width=0, noindent=False, query=u'{"term": {"uuid": "145eab3b-9296-4b31-939f-01e44feb39a5"}}', quote_mode='nonnumeric', source='all_sources', type=None))
take_action(Namespace(all_projects=False, columns=[], formatter='table', json=True, max_width=0, noindent=False, query=u'{"term": {"uuid": "145eab3b-9296-4b31-939f-01e44feb39a5"}}', quote_mode='nonnumeric', source='all_sources', type=None))
Making authentication request to http://192.168.122.156/identity/v2.0/tokens
"POST /identity/v2.0/tokens HTTP/1.1" 200 3042
REQ: curl -g -i -X POST http://192.168.122.156:9393/v1/search -H "User-Agent: python-searchlightclient" -H "Content-Type: application/json" -H "Accept: application/json" -H "X-Auth-Token: {SHA1}a885d2679d8e2e5945b939bb2efda7fa016f0fcf" -d '{"query": {"term": {"uuid": "145eab3b-9296-4b31-939f-01e44feb39a5"}}, "type": null, "all_projects": false}'
Starting new HTTP connection (1): 192.168.122.156
"POST /v1/search HTTP/1.1" 200 694
RESP: [200] Content-Length: 694 Content-Type: application/json; charset=UTF-8 X-Openstack-Request-Id: req-f96e5cb9-1161-43a8-a927-64c14f5c1461 Date: Wed, 07 Sep 2016 11:51:11 GMT Connection: keep-alive
RESP BODY: {"hits": {"hits": [{"_type": "OS::Ironic::Port", "_routing": "6e175dbf-bcc6-43a7-a42f-d82c1ef5f4e0", "_index": "searchlight-2016_09_01_14_56_14", "_score": 5.069027, "_source": {"local_link_connection": {}, "node_uuid": "6e175dbf-bcc6-43a7-a42f-d82c1ef5f4e0", "uuid": "145eab3b-9296-4b31-939f-01e44feb39a5", "extra": {}, "pxe_enabled": true, "created_at": "2016-09-05T11:47:32Z", "updated_at": "2016-09-05T11:50:14Z", "address": "22:55:66:77:88:aa", "internal_info": {}}, "_parent": "6e175dbf-bcc6-43a7-a42f-d82c1ef5f4e0", "_id": "145eab3b-9296-4b31-939f-01e44feb39a5"}], "total": 1, "max_score": 5.069027}, "_shards": {"successful": 5, "failed": 0, "total": 5}, "took": 24, "timed_out": false}

u'_routing'
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/cliff/app.py", line 387, in run_subcommand
    result = cmd.run(parsed_args)
  File "/usr/local/lib/python2.7/dist-packages/osc_lib/command/command.py", line 41, in run
    return super(Command, self).run(parsed_args)
  File "/usr/local/lib/python2.7/dist-packages/cliff/display.py", line 100, in run
    column_names, data = self.take_action(parsed_args)
  File "/opt/stack/python-searchlightclient/searchlightclient/osc/v1/search.py", line 121, in take_action
    converted[mapping[k]] = v
KeyError: u'_routing'
clean_up SearchResource: u'_routing'
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/osc_lib/shell.py", line 135, in run
    ret_val = super(OpenStackShell, self).run(argv)
  File "/usr/local/lib/python2.7/dist-packages/cliff/app.py", line 267, in run
    result = self.run_subcommand(remainder)
  File "/usr/local/lib/python2.7/dist-packages/osc_lib/shell.py", line 180, in run_subcommand
    ret_value = super(OpenStackShell, self).run_subcommand(argv)
  File "/usr/local/lib/python2.7/dist-packages/cliff/app.py", line 387, in run_subcommand
    result = cmd.run(parsed_args)
  File "/usr/local/lib/python2.7/dist-packages/osc_lib/command/command.py", line 41, in run
    return super(Command, self).run(parsed_args)
  File "/usr/local/lib/python2.7/dist-packages/cliff/display.py", line 100, in run
    column_names, data = self.take_action(parsed_args)
  File "/opt/stack/python-searchlightclient/searchlightclient/osc/v1/search.py", line 121, in take_action
    converted[mapping[k]] = v
KeyError: u'_routing'