(byebug) client.use(:admin).command(getParameter: 1, featureCompatibilityVersion: 1)
*** Mongo::Error::OperationFailure Exception: no option found to get ()

speed% mongo --port 29400
MongoDB shell version v3.6.9
connecting to: mongodb://127.0.0.1:29400/
Implicit session: session { "id" : UUID("fcdf70ad-6fb0-4e84-b880-2d762d4030fb") }
MongoDB server version: 4.0.4-92-ga3ed66ac2e
WARNING: shell and server versions do not match
Server has startup warnings: 
2019-01-16T14:42:39.279-0500 I CONTROL  [main] 
2019-01-16T14:42:39.279-0500 I CONTROL  [main] ** WARNING: Access control is not enabled for the database.
2019-01-16T14:42:39.279-0500 I CONTROL  [main] **          Read and write access to data and configuration is unrestricted.
2019-01-16T14:42:39.279-0500 I CONTROL  [main] 
2019-01-16T14:42:39.279-0500 I CONTROL  [main] ** WARNING: This server is bound to localhost.
2019-01-16T14:42:39.279-0500 I CONTROL  [main] **          Remote systems will be unable to connect to this server. 
2019-01-16T14:42:39.279-0500 I CONTROL  [main] **          Start the server with --bind_ip <address> to specify which IP 
2019-01-16T14:42:39.279-0500 I CONTROL  [main] **          addresses it should serve responses from, or with --bind_ip_all to
2019-01-16T14:42:39.279-0500 I CONTROL  [main] **          bind to all interfaces. If this behavior is desired, start the
2019-01-16T14:42:39.279-0500 I CONTROL  [main] **          server with --bind_ip 127.0.0.1 to disable this warning.
2019-01-16T14:42:39.279-0500 I CONTROL  [main] 
mongos> db.adminCommand( { getParameter: 1, featureCompatibilityVersion: 1 } )
{
	"ok" : 0,
	"errmsg" : "no option found to get",
	"operationTime" : Timestamp(1547668183, 1),
	"$clusterTime" : {
		"clusterTime" : Timestamp(1547668183, 1),
		"signature" : {
			"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
			"keyId" : NumberLong(0)
		}
	}
}