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

def stats(self, index=None, metric=None, params=None):
        """
        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
        """
        return self.transport.perform_request(
            "GET", _make_path(index, "_stats", metric), params=params
        )