code: func (vertices vertices) String() string {
  	result := ``
  	for i, v := range vertices {
  		result += fmt.Sprintf(`VERTEX INDEX: %+v, VERTEX: %+v`, i, v)
  		result += fmt.Sprintln(``)
  	}
  
  	return result
  }
docs: // String prints out a string representation of every vertex in this list.
  // Useful for debugging :).