code: func (st *Stack) Print() {
  	fmt.Println("### stack ###")
  	if len(st.data) > 0 {
  		for i, val := range st.data {
  			fmt.Printf("%-3d  %v\n", i, val)
  		}
  	} else {
  		fmt.Println("-- empty --")
  	}
  	fmt.Println("#############")
  }
docs: // Print dumps the content of the stack