sclass BitGetCredentials {
  settable S apiKey;
  settable S passphrase;
  settable S secretKey;
  
  toString {
    ret joinNempties(" with ", shortClassName(this),
      commaCombine(
        nempty(apiKey) ? "apiKey" : null,
        nempty(passphrase) ? "passphrase" : null,
        nempty(secretKey) ? "secretKey" : null));
  }
}