code: function lookupKeyOrProperty(target, keyOrProperty /*| keyof T*/) {
      // get the class constructor
      const constr = target.constructor;
      // retrieve the current metadata
      const metadata = Reflect.getMetadata(METADATA_ipsoKey, constr);
      return metadata && metadata[keyOrProperty];
  }
docs: Looks up previously stored property ipso key definitions.
  Returns a property name if the key was given, or the key if a property name was given.
  @param keyOrProperty - ipso key or property name to lookup