code: func (v *Errors) Add(key string, msg string) {
  	v.Lock.Lock()
  	v.Errors[key] = append(v.Errors[key], msg)
  	v.Lock.Unlock()
  }
docs: // Add will add a new message to the list of errors using
  // the given key. If the key already exists the message will
  // be appended to the array of the existing messages.