code: static String asString(Object value) throws ProvidenceConfigException {
          if (value instanceof Collection || value instanceof Map) {
              throw new ProvidenceConfigException(
                      "Unable to convert " + value.getClass().getSimpleName() + " to a string");
          } else if (value instanceof Stringable) {
              return ((Stringable) value).asString();
          } else if (value instanceof Date) {
              Instant instant = ((Date) value).toInstant();
              return DateTimeFormatter.ISO_INSTANT.format(instant);
          }
          return Objects.toString(value);
      }
docs: Convert the value to a string.
  
  @param value The value instance.
  @return The string value.
  @throws ProvidenceConfigException When unable to convert value.