code: def test_loop_initializing_variant_variable_illegal(self, n):
      with self.assertRaisesRegex(
          ValueError, "must be defined before the loop"
      ):
          tf.function(loop_initializing_variant_variable)(
              tf.constant(n)
          )
  
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 19 for calling the NestedControlFlowTest obj's underlying member method code with example usage: obj.test_loop_initializing_variant_variable_illegal(n) without return types