code: public CMAWebhook create(String spaceId, CMAWebhook webhook) {
      assertNotNull(spaceId, "spaceId");
      assertNotNull(webhook, "webhook");
      final String webhookId = webhook.getId();
  
      final CMASystem system = webhook.getSystem();
      webhook.setSystem(null);
      try {
        if (webhookId == null) {
          return service.create(spaceId, webhook).blockingFirst();
        } else {
          return service.create(spaceId, webhookId, webhook).blockingFirst();
        }
      } finally {
        webhook.setSystem(system);
      }
    }
docs: Create a new webhook.
  <p>
  This will create a new ID and return the newly created webhook as a return value.
  <p>
  This method will override the configuration specified through
  {@link CMAClient.Builder#setSpaceId(String)} and will ignore
  {@link CMAClient.Builder#setEnvironmentId(String)}.
  
  @param spaceId Which space should be used?
  @param webhook A representation of the Webhook to be used.
  @return The webhook returned from the backend, containing created its ID and more.
  @throws IllegalArgumentException if space id is null.
  @throws IllegalArgumentException if webhook is null.