def add(contacts)
      contact_ids = [contacts].flatten.uniq.compact.map(&:id)
      response = Hubspot::Connection.post_json(ADD_CONTACT_PATH, params: { list_id: @id }, body: { vids: contact_ids })
      response['updated'].sort == contact_ids.sort
    end
def add(contacts)
      contact_ids = [contacts].flatten.uniq.compact.map(&:id)
      response = Hubspot::Connection.post_json(ADD_CONTACT_PATH, params: { list_id: @id }, body: { vids: contact_ids })
      response['updated'].sort == contact_ids.sort
    end
{http://developers.hubspot.com/docs/methods/lists/add_contact_to_list}