code: def test_getSingleImageDataById_isBlank(self):
      returnedImageData = (
          self.imageDataExtractor.getSingleImageDataById(imageId=" ")
      )
      self.assertIsNone(returnedImageData)
  
imports: import sys
  import unittest
  from typing import Dict, List
  from MONAILabelReviewerLib.ImageData import ImageData
  from MONAILabelReviewerLib.ImageDataExtractor import ImageDataExtractor
  from MONAILabelReviewerLib.MONAILabelReviewerEnum import Level, SegStatus
label_desc: Use image node_id 25 for calling the ImageDataExtractorTest obj's underlying member method code with example usage: obj.test_getSingleImageDataById_isBlank() without return types