code: def testFlush(self):
      estimator = size_estimator.SizeEstimator(
          size_threshold=10, size_fn=len
      )
      self.assertEqual(estimator.get_estimate(), 0)
      estimator.update(b"plmjh")
      estimator.update(b"plmjhghytfghsggssss")
      self.assertTrue(estimator.should_flush())
      estimator.clear()
      self.assertEqual(estimator.get_estimate(), 0)
  
imports: import sys
  import tensorflow
  from tensorflow_model_analysis.utils import size_estimator
label_desc: Use image node_id 2 for calling the SizeEstimatorTest obj's underlying member method code with example usage: obj.testFlush() without return types