code: def test_while_imbalanced_illegal(self):
      with self.assertRaisesRegex(
          tf.errors.InvalidArgumentError,
          r"loop must iterate at least once to initialize y\[\\'a\\'\]",
      ):
          tf.function(while_imbalanced)(tf.constant(11))
  
imports: import itertools
  from absl.testing import parameterized
  import tensorflow
  from tensorflow.python.autograph.tests import reference_test_base
label_desc: Use image node_id 7 for calling the ReferenceTest obj's underlying member method code with example usage: obj.test_while_imbalanced_illegal() without return types