code: func RemoveContact(c *messagebird.Client, groupID, contactID string) error {
  	formattedPath := fmt.Sprintf("%s/%s/contacts/%s", path, groupID, contactID)
  
  	return c.Request(nil, http.MethodDelete, formattedPath, nil)
  }
docs: // RemoveContact removes the contact from a group. If nil is returned, the
  // operation was successful.