code: public void setApiKey(String apiKey) {
          for (Authentication auth : authentications.values()) {
              if (auth instanceof ApiKeyAuth) {
                  ((ApiKeyAuth) auth).setApiKey(apiKey);
                  return;
              }
          }
          throw new RuntimeException("No API key authentication configured!");
      }
docs: Helper method to set API key value for the first API key authentication.
  
  @param apiKey API key