code: public Optional<String> getString(String key) {
          Objects.requireNonNull(key, Required.KEY.toString());
  
          String value = this.values.get(key);
          if (StringUtils.isNotBlank(value)) {
              return Optional.of(value);
          }
  
          return Optional.empty();
      }
docs: Retrieves an optional string value corresponding to the name of the form element
  
  @param key The name of the form element
  @return Optional of String