code: def follow(self, index, body, params=None):
          
          for param in (index, body):
              if param in SKIP_IN_PATH:
                  raise ValueError("Empty value passed for a required argument.")
          return self.transport.perform_request(
              "PUT", _make_path(index, "_ccr", "follow"), params=params, body=body
          )
docs: `<https://www.elastic.co/guide/en/elasticsearch/reference/current/ccr-put-follow.html>`_
  
          :arg index: The name of the follower index
          :arg body: The name of the leader index and other optional ccr related
              parameters
          :arg wait_for_active_shards: Sets the number of shard copies that must
              be active before returning. Defaults to 0. Set to `all` for all
              shard copies, otherwise set to any non-negative value less than or
              equal to the total number of copies for the shard (number of
              replicas + 1), default '0'