docs: public static AssertionInfo getAssertion(Message message)
              throws SAXException, IOException, ParserConfigurationException {
          AssertionInfoMap aim = message.get(AssertionInfoMap.class);
  
          if (aim != null) {
              Collection<AssertionInfo> ais = aim
                      .get(TransformationPolicyBuilder.TRANSFORMATION);
  
              if (ais == null) {
                  return null;
              }
  
              for (AssertionInfo ai : ais) {
                  if (ai.getAssertion() instanceof TransformationAssertion) {
                      return ai;
                  }
              }
          }
  
          return null;
      }