old_contents: import pytest
  
  from attr._compat import metadata_proxy
  
  
  @pytest.fixture(name="mp")
  def _mp():
      return metadata_proxy({"x": 42, "y": "foo"})
  
  
  class TestMetadataProxy:
      """
      Ensure properties of metadata_proxy independently of hypothesis strategies.
      """
  
      def test_repr(self, mp):
          """
          repr makes sense and is consistent across Python versions.
          """
          assert any(
              [
                  "mappingproxy({'x': 42, 'y': 'foo'})" == repr(mp),
                  "mappingproxy({'y': 'foo', 'x': 42})" == repr(mp),
              ]
          )
  
      def test_immutable(self, mp):
          """
          All mutating methods raise errors.
          """
          with pytest.raises(TypeError, match="not support item assignment"):
              mp["z"] = 23
  
          with pytest.raises(TypeError, match="not support item deletion"):
              del mp["x"]
  
          with pytest.raises(AttributeError, match="no attribute 'update'"):
              mp.update({})
  
          with pytest.raises(AttributeError, match="no attribute 'clear'"):
              mp.clear()
  
          with pytest.raises(AttributeError, match="no attribute 'pop'"):
              mp.pop("x")
  
          with pytest.raises(AttributeError, match="no attribute 'popitem'"):
              mp.popitem("x")
  
          with pytest.raises(AttributeError, match="no attribute 'setdefault'"):
              mp.setdefault("x")
  
new_contents: import pytest
  
  from attr._compat import metadata_proxy
  
  
  @pytest.fixture(name="mp")
  def _mp():
      return metadata_proxy({"x": 42, "y": "foo"})
  
  
  class TestMetadataProxy:
      """
      Ensure properties of metadata_proxy independently of hypothesis strategies.
      """
  
      def test_repr(self, mp):
          """
          repr makes sense and is consistent across Python versions.
          """
          assert any(
              [
                  "mappingproxy({'x': 42, 'y': 'foo'})" == repr(mp),
                  "mappingproxy({'y': 'foo', 'x': 42})" == repr(mp),
              ]
          )
  
      def test_immutable(self, mp):
          """
          All mutating methods raise errors.
          """
          with pytest.raises(TypeError, match="not support item assignment"):
              mp["z"] = 23
  
          with pytest.raises(TypeError, match="not support item deletion"):
              del mp["x"]
  
          with pytest.raises(AttributeError, match="no attribute 'update'"):
              mp.update({})
  
          with pytest.raises(AttributeError, match="no attribute 'clear'"):
              mp.clear()
  
          with pytest.raises(AttributeError, match="no attribute 'pop'"):
              mp.pop("x")
  
          with pytest.raises(AttributeError, match="no attribute 'popitem'"):
              mp.popitem()
  
          with pytest.raises(AttributeError, match="no attribute 'setdefault'"):
              mp.setdefault("x")
  
subject: Fix Python 2