code: public CMAApiKey create(String spaceId, CMAApiKey key) {
      assertNotNull(spaceId, "spaceId");
      assertNotNull(key, "key");
  
      return service.create(spaceId, key).blockingFirst();
    }
docs: Create a new delivery api key.
  
  @param spaceId the id of the space this is valid on.
  @param key     the key to be created.
  @return the just created key, containing the delivery token.
  @throws IllegalArgumentException if spaceId is null.
  @throws IllegalArgumentException if key is null.