docs: public static Map<String, String> flattenDataContext(final Map<String, Map<String, String>> dataContext) {
          final Map<String, String> res = new HashMap<String, String>();
          if(null!=dataContext){
              for (final Map.Entry<String, Map<String, String>> entry : dataContext.entrySet()) {
  
                  final String p = entry.getKey() + ".";
                  final Map<String, String> map = entry.getValue();
                  if(null!=map){
                      for (final Map.Entry<String, String> entry2 : map.entrySet()) {
                          if(null!=map.get(entry2.getKey())){
                              res.put(p + entry2.getKey(), entry2.getValue());
                          }
                      }
                  }
              }
          }
          return res;
      }