code: def stats(self, index=None, metric=None, params=None):
          
          return self.transport.perform_request(
              "GET", _make_path(index, "_stats", metric), params=params
          )
docs: Retrieve statistics on different operations happening on an index.
          `<http://www.elastic.co/guide/en/elasticsearch/reference/current/indices-stats.html>`_
  
          :arg index: A comma-separated list of index names; use `_all` or empty
              string to perform the operation on all indices
          :arg metric: Limit the information returned the specific metrics.
          :arg completion_fields: A comma-separated list of fields for `fielddata`
              and `suggest` index metric (supports wildcards)
          :arg fielddata_fields: A comma-separated list of fields for `fielddata`
              index metric (supports wildcards)
          :arg fields: A comma-separated list of fields for `fielddata` and
              `completion` index metric (supports wildcards)
          :arg groups: A comma-separated list of search groups for `search` index
              metric
          :arg include_segment_file_sizes: Whether to report the aggregated disk
              usage of each one of the Lucene index files (only applies if segment
              stats are requested), default False
          :arg level: Return stats aggregated at cluster, index or shard level,
              default 'indices', valid choices are: 'cluster', 'indices', 'shards'
          :arg types: A comma-separated list of document types for the `indexing`
              index metric