anchor.diff:  
   type TrainArgs =
       | [<MainCommand; ExactlyOnce; Last; Mandatory>] CfgFile of filename:string
  +    | Restart
       with
       interface IArgParserTemplate with member s.Usage = "self-explaining"
   
  
positive.code: 
          | Train args ->
              let cfgFile = args.GetResult <@ CfgFile @>
              let mi, predFn, trainFn = buildModel cfgFile
              let tr = trainFn ()
              printfn "%A" tr.Best
              printfn "Used config was %s" cfgFile
  
          0
negative.code:                 mi.SavePars filename
              
          // build training function
          let trainCfg = {cfg.Training with LossRecordFunc=lossRecordFn; DiscardCheckpoint=restart}        
          let trainFn () = 
              Train.train trainable dataset trainCfg
  
  