code: def test_variable_paddings(self):
      x = tf.Variable([[1, 2]])
      b = pad.Pad(paddings=x, validate_args=True)
      y = b.forward([[1, 2]])
      self.evaluate(b.paddings.initializer)
      self.assertAllEqual([[0, 1, 2, 0, 0]], self.evaluate(y))
      with tf.control_dependencies([b.paddings.assign([[1, 0]])]):
          y = b.forward([[1, 2]])
      self.assertAllEqual([[0, 1, 2]], self.evaluate(y))
  
file_path: probability/tensorflow_probability/python/bijectors/pad_test.py
imports: import tensorflow.compat.v1
  import tensorflow.compat.v2
  from tensorflow_probability.python.bijectors import pad
  from tensorflow_probability.python.internal import test_util
label_desc: Use image node_id 3 for calling the PadBijectorTest obj's underlying member method code with example usage: obj.test_variable_paddings() without return types