code: public CMAContentType update(CMAContentType contentType) {
      assertNotNull(contentType, "contentType");
      assertNotNull(contentType.getName(), "contentType.name");
  
      final String contentTypeId = getResourceIdOrThrow(contentType, "contentType");
      final String spaceId = getSpaceIdOrThrow(contentType, "contentType");
      final String environmentId = contentType.getEnvironmentId();
      final Integer version = getVersionOrThrow(contentType, "update");
  
      final CMASystem system = contentType.getSystem();
      contentType.setSystem(null);
  
      try {
        return service.update(
            version,
            spaceId,
            environmentId,
            contentTypeId,
            contentType
        ).blockingFirst();
      } finally {
        contentType.setSystem(system);
      }
    }
docs: Update a Content Type.
  
  @param contentType Content Type
  @return {@link CMAContentType} result instance
  @throws IllegalArgumentException if contentType is null.
  @throws IllegalArgumentException if contentType's name is null.
  @throws IllegalArgumentException if contentType's id is null.
  @throws IllegalArgumentException if contentType's space id is null.
  @throws IllegalArgumentException if contentType's version is null.