code: def test_blank_image(self):
      image = np.zeros([100, 100, 3], dtype=np.uint8)
      image.fill(255)
      with mp_faces.FaceDetection(
          min_detection_confidence=0.5
      ) as faces:
          results = faces.process(image)
          self.assertIsNone(results.detections)
  
file_path: mediapipe/mediapipe/python/solutions/face_detection_test.py
imports: import os
  import tempfile
  from typing import NamedTuple
  from absl.testing import absltest
  from absl.testing import parameterized
  import cv2
  import numpy
  import numpy.testing
  from mediapipe.python.solutions import drawing_utils
  from mediapipe.python.solutions import face_detection
label_desc: Use image node_id 3 for calling the FaceDetectionTest obj's underlying member method code with example usage: obj.test_blank_image() without return types