code: def testUnknownInputSize(self):
      x = tf.TensorSpec([None, None], dtype=tf.float32)
  
      l = linear.Linear(3)
      defun_linear = tf.function(l)
  
      with self.assertRaisesRegex(
          ValueError,
          "Input size must be specified at module build time.",
      ):
          defun_linear.get_concrete_function(x)
  
imports: from absl.testing import parameterized
  import numpy
  from sonnet.src import linear
  from sonnet.src import test_utils
  import tensorflow
label_desc: Use image node_id 12 for calling the LinearTest obj's underlying member method code with example usage: obj.testUnknownInputSize() without return types