def rest_xml
      doc = REXML::Document.new APIConnection::XML_HEADER
      obj = doc.add_element RSRC_OBJECT_KEY.to_s
      obj.add_element('invitation_type').text = invitation_type
      obj.add_element('create_account_if_does_not_exist').text = create_account_if_does_not_exist
      if expiration_date_epoch
        obj.add_element('expiration_date_epoch').text = expiration_date_epoch
      end
      obj.add_element('ssh_username').text = ssh_username
      obj.add_element('hide_account').text = hide_account
      obj.add_element('invitation_status').text = invitation_status
      obj.add_element('multiple_uses_allowed').text = multiple_uses_allowed
      add_site_to_xml(doc)
      doc.to_s
    end
def rest_xml
      doc = REXML::Document.new APIConnection::XML_HEADER
      obj = doc.add_element RSRC_OBJECT_KEY.to_s
      obj.add_element('invitation_type').text = invitation_type
      obj.add_element('create_account_if_does_not_exist').text = create_account_if_does_not_exist
      if expiration_date_epoch
        obj.add_element('expiration_date_epoch').text = expiration_date_epoch
      end
      obj.add_element('ssh_username').text = ssh_username
      obj.add_element('hide_account').text = hide_account
      obj.add_element('invitation_status').text = invitation_status
      obj.add_element('multiple_uses_allowed').text = multiple_uses_allowed
      add_site_to_xml(doc)
      doc.to_s
    end
Sets invitation expiration 4 hours after request.