code: private void mergeOneOf() {
          if (SchemaCompositeMatchers.hasOneOf().matches(schema)) {
              SchemaList list = schema.getOneOf();
              Schema choice = list.get(rnd.nextInt(list.size()));
              schema.getJson().remove("oneOf");
              schema.merge(choice);
          }
      }
docs: TODO dirty and incorrect for overlaps