code: public JsonFluentAssert isNotEqualTo(Object expected) {
          Diff diff = createDiff(expected, configuration);
          if (diff.similar()) {
              failWithMessage("JSON is equal.");
          }
          return this;
      }
docs: Fails if compared documents are equal. The expected object is converted to JSON
  before comparison. Ignores order of sibling nodes and whitespaces.
  
  @param expected
  @return {@code this} object.