getContext = representative => {
    representative ||
      // separate line to ease breakpointing
      Fail`Method ${methodTag} called without 'this' object`;
    const context = contextProvider(representative);
    if (context === undefined) {
      throw Fail`${q(
        methodTag,
      )} may only be applied to a valid instance: ${representative}`;
    }
    return context;
  }
@param {any} representative
@returns {ClassContext | KitContext}