code: def test_is_immutable(self):
      with self.assertRaises(TypeError):
          self.row[0] = "foo"
  
      with self.assertRaises(TypeError):
          self.row["one"] = 100
  
imports: import unittest
  from agate.mapped_sequence import MappedSequence
label_desc: Use image node_id 2 for calling the TestMappedSequence obj's underlying member method code with example usage: obj.test_is_immutable() without return types