code: public void addUserArtifact(String name, DistributedCache.DistributedCacheEntry file) {
  		if (file == null) {
  			throw new IllegalArgumentException();
  		}
  
  		userArtifacts.putIfAbsent(name, file);
  	}
docs: Adds the path of a custom file required to run the job on a task manager.
  
  @param name a name under which this artifact will be accessible through {@link DistributedCache}
  @param file path of a custom file required to run the job on a task manager