code: func FromArgs(args []string, fn func(Boxes) error) error {
  	if len(args) == 0 {
  		return errors.New("you must supply a payload")
  	}
  	payload := args[0]
  	if len(payload) == 0 {
  		return errors.New("you must supply a payload")
  	}
  
  	var boxes Boxes
  	err := json.Unmarshal([]byte(payload), &boxes)
  	if err != nil {
  		return err
  	}
  
  	return fn(boxes)
  }
docs: // FromArgs is useful when writing packr store-cmd binaries.
  /*
  	package main
  
  	import (
  		"log"
  		"os"
  
  		"github.com/gobuffalo/packr/v2/jam/parser"
  		"github.com/markbates/s3packr/s3packr"
  	)
  
  	func main() {
  		err := parser.FromArgs(os.Args[1:], func(boxes parser.Boxes) error {
  			for _, box := range boxes {
  				s3 := s3packr.New(box)
  				if err := s3.Pack(box); err != nil {
  					return err
  				}
  			}
  			return nil
  		})
  
  		if err != nil {
  			log.Fatal(err)
  		}
  	}
  */