code: func funcPredictLinear(vals []Value, args Expressions, enh *EvalNodeHelper) Vector {
  	mat := vals[0].(Matrix)
  	duration := vals[1].(Vector)[0].V
  
  	for _, samples := range mat {
  		// No sense in trying to predict anything without at least two points.
  		// Drop this Vector element.
  		if len(samples.Points) < 2 {
  			continue
  		}
  		slope, intercept := linearRegression(samples.Points, enh.ts)
  
  		enh.out = append(enh.out, Sample{
  			Point: Point{V: slope*duration + intercept},
  		})
  	}
  	return enh.out
  }
docs: // === predict_linear(node ValueTypeMatrix, k ValueTypeScalar) Vector ===