code: def test_domain(self):
      # Test that the domain parameter is required and is a string
      with self.assertRaises(TypeError):
          defs.OpSchema(name="test_op", since_version=1)  # type: ignore
      with self.assertRaises(TypeError):
          defs.OpSchema("test_op", 123, 1)  # type: ignore
  
      schema = defs.OpSchema("test_op", "test_domain", 1)
      self.assertEqual(schema.domain, "test_domain")
  
imports: import unittest
  from typing import Sequence
  import parameterized
  import onnx
  from onnx import defs
label_desc: Use image node_id 6 for calling the TestOpSchema obj's underlying member method code with example usage: obj.test_domain() without return types