code: func Create(c *messagebird.Client, recipients []string, body string, params *Params) (*VoiceMessage, error) {
  	requestData, err := requestDataForVoiceMessage(recipients, body, params)
  	if err != nil {
  		return nil, err
  	}
  
  	message := &VoiceMessage{}
  	if err := c.Request(message, http.MethodPost, path, requestData); err != nil {
  		return nil, err
  	}
  
  	return message, nil
  }
docs: // Create a new voice message for one or more recipients.