 
 extension Reward: StringEnumArgument {
   public static var completion: ShellCompletion {
-    return .values([
+    .values([
       (Reward.collectJellyBeans.rawValue, "Each collected jelly bean is worth 1 point."),
       (Reward.collectOnions.rawValue, "Each collected onion is worth 1 point."),
       (Reward.collectJellyBeansAvoidOnions.rawValue, "Each collected jelly bean is worth 1 point and each collected onion -1 point."),


extension Network: StringEnumArgument {
  public static var completion: ShellCompletion {
    return .values([
      (Network.plain.rawValue, "Plain network."),
      (Network.contextual.rawValue, "Contextual network.")
    ])


extension Observation: StringEnumArgument {
  public static var completion: ShellCompletion {
    .values([
      (Observation.vision.rawValue, "Visual field."),
      (Observation.scent.rawValue, "Scent vector at the current cell."),
      (Observation.visionAndScent.rawValue, "Visual field and scent vector at the current cell.")
