docs: public static void recursivelySquashNulls(Object input) {
  
          // Makes two passes thru the data.
          Objects.squashNulls( input );
  
          if ( input instanceof List ) {
              List inputList = (List) input;
              inputList.forEach( i -> recursivelySquashNulls( i ) );
          }
          else if ( input instanceof Map ) {
              Map<String,Object> inputMap = (Map<String,Object>) input;
  
              for (Map.Entry<String,Object> entry : inputMap.entrySet()) {
                  recursivelySquashNulls( entry.getValue() );
              }
          }
      }