code: public static Predicate<HandlerInput> persistentAttribute(String key, Object value) {
          return i -> i.getAttributesManager().getPersistentAttributes().containsKey(key)
                  && value.equals(i.getAttributesManager().getPersistentAttributes().get(key));
      }
docs: Returns a predicate that returns to true if the persistent attributes included with the {@link HandlerInput}
  contain the expected attribute value.
  @param key key of the attribute to evaluate
  @param value value of the attribute to evaluate
  @return true if the persistent attributes included with the {@link HandlerInput} contain the expected
  attribute value