code: def testEmptyMatch(self, op):
      values = ["abc", "1"]
      with self.cached_session():
          input_vector = constant_op.constant(values, dtypes.string)
          stripped = op(input_vector, "", "x")
          self.assertAllEqual([b"xaxbxcx", b"x1x"], stripped)
  
imports: from absl.testing import parameterized
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import gen_string_ops
  from tensorflow.python.ops import string_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 4 for calling the RegexReplaceOpVariantsTest obj's underlying member method code with example usage: obj.testEmptyMatch(op) without return types