Account for Python 3.7 in the 7.4.x branch

Author: nicoddemus

src/_pytest/doctest.py

@@ -545,7 +545,9 @@ def _from_module(self, module, object):
                     Here we override `_from_module` to check the underlying
                     function instead. https://github.com/python/cpython/issues/107995
                     """
-                    if isinstance(object, functools.cached_property):
+                    if hasattr(functools, "cached_property") and isinstance(
+                        object, functools.cached_property
+                    ):
                         object = object.func
 
                     # Type ignored because this is a private function.

testing/test_doctest.py

@@ -482,6 +482,9 @@ def test_doctestmodule(self, pytester: Pytester):
         reprec = pytester.inline_run(p, "--doctest-modules")
         reprec.assertoutcome(failed=1)
 
+    @pytest.mark.skipif(
+        sys.version_info[:2] <= (3, 7), reason="Only Python 3.7 or less"
+    )
     def test_doctest_cached_property(self, pytester: Pytester):
         p = pytester.makepyfile(
             """