code: def testString(self):
      # Numpy does not support padding strings so we compare padding manually.
      x = ops.convert_to_tensor(
          [["Hello", "World"], ["Goodnight", "Moon"]]
      )
  
      constant = array_ops.pad(
          x, [[1, 0], [0, 1]], mode="CONSTANT", constant_values="PAD"
      )
      reflect = array_ops.pad(
          x, [[1, 0], [0, 1]], mode="REFLECT", constant_values="PAD"
      )
      symmetric = array_ops.pad(
          x, [[1, 0], [0, 1]], mode="SYMMETRIC", constant_values="PAD"
      )
      with test_util.use_gpu():
          self.assertAllEqual(
              [
                  [b"PAD", b"PAD", b"PAD"],
                  [b"Hello", b"World", b"PAD"],
                  [b"Goodnight", b"Moon", b"PAD"],
              ],
              self.evaluate(constant),
          )
          self.assertAllEqual(
              [
                  [b"Goodnight", b"Moon", b"Goodnight"],
                  [b"Hello", b"World", b"Hello"],
                  [b"Goodnight", b"Moon", b"Goodnight"],
              ],
              self.evaluate(reflect),
          )
          self.assertAllEqual(
              [
                  [b"Hello", b"World", b"World"],
                  [b"Hello", b"World", b"World"],
                  [b"Goodnight", b"Moon", b"Moon"],
              ],
              self.evaluate(symmetric),
          )
  
imports: import numpy
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import gradient_checker_v2
  from tensorflow.python.platform import test
label_desc: Use image node_id 22 for calling the PadOpTest obj's underlying member method code with example usage: obj.testString() without return types