code: def testReplaceUnknownFields(self):
      t = structural_tuple.structtuple(["a"])
      a = t()
      with self.assertRaisesRegexp(
          ValueError, r"Got unexpected field names: \[\'b\', \'c\'\]"
      ):
          a._replace(b=1, c=2)
  
imports: import tensorflow.compat.v2
  from tensorflow_probability.python.internal import nest_util
  from tensorflow_probability.python.internal import structural_tuple
  from tensorflow_probability.python.internal import test_util
  from tensorflow.python.util import nest
label_desc: Use image node_id 18 for calling the StructTupleTest obj's underlying member method code with example usage: obj.testReplaceUnknownFields() without return types