docs: function predictOneDT(inst) { 
      
      var n=0;
      for(var i=0;i<this.maxDepth;i++) {
          var dir= this.testFun(inst, this.models[n]);
          if(dir === 1) n= n*2+1; // descend left
          else n= n*2+2; // descend right
      }
      
      return (this.leafPositives[n] + 0.5) / (this.leafNegatives[n] + 1.0); // bayesian smoothing!
  }