tag error

127.0.0.1 - - [23/May/2017 00:51:59] "POST /tag HTTP/1.1" 500 -
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1997, in __call__
    return self.wsgi_app(environ, start_response)
  File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1985, in wsgi_app
    response = self.handle_exception(e)
  File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1540, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1982, in wsgi_app
    response = self.full_dispatch_request()
  File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1614, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/usr/local/lib/python2.7/dist-packages/flask_api/app.py", line 103, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1612, in full_dispatch_request
    rv = self.dispatch_request()
  File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1598, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/home/kbot/hybrid_tagger/4_run_api.py", line 36, in tag
    tags = ct.tag(data['text'],show_groups=data['show_groups'],show_unconfirmed=data['show_unconfirmed'])
  File "/home/kbot/hybrid_tagger/tagger/taggers.py", line 105, in tag
    tag_candidates = self.es.get_tag_candidates(text,num_candidates)
  File "/home/kbot/hybrid_tagger/tagger/elasticsearch.py", line 63, in get_tag_candidates
    for hit in response['hits']['hits']:
KeyError: 'hits'