code: def test_canonicalize_padding(self):
      def test_pad(pad, rank, expected=None):
          if expected is None:
              with self.assertRaises(ValueError):
                  nn.linear.canonicalize_padding(pad, rank)
          else:
              self.assertEqual(
                  nn.linear.canonicalize_padding(pad, rank), expected
              )
  
      test_pad("SAME", 2, "SAME")
      test_pad(2, 3, [(2, 2), (2, 2), (2, 2)])
      test_pad((2, 2), 3)
      test_pad((2, 2), 1)
      test_pad([1, (2, 3)], 2, [(1, 1), (2, 3)])
      test_pad([None, (1, 2)], 2)
  
imports: import functools
  import jax
  import jax.numpy
  import numpy
  from absl.testing import absltest, parameterized
  from jax import random
  from jax.nn import initializers
  from flax import linen
label_desc: Use image node_id 47 for calling the LinearTest obj's underlying member method code with example usage: obj.test_canonicalize_padding() without return types