docs: private Map<String, String> convertToMap(Object expression) {
          if (expression instanceof Map) {
              return (Map<String, String>) expression;
          }
  
          return Stream.of(Optional.ofNullable(expression)
                  .map(Object::toString)
                  .orElse("")
                  .split(","))
                  .map(keyValue -> Optional.ofNullable(StringUtils.split(keyValue, "=")).orElse(new String[] {keyValue, ""}))
                  .collect(Collectors.toMap(keyValue -> keyValue[0], keyValue -> keyValue[1]));
      }