code: func NewPot(v Val, po int) *Pot {
  	var size int
  	if v != nil {
  		size++
  	}
  	return &Pot{
  		pin:  v,
  		po:   po,
  		size: size,
  	}
  }
docs: // NewPot constructor. Requires a value of type Val to pin
  // and po to point to a span in the Val key
  // The pinned item counts towards the size