Skip pre python 3.5

conftest.py

@@ -148,3 +148,11 @@ def skip_pre_python37(environment):
         # This if is just needed to avoid that tests ever skip way more than
         # they should for all Python versions.
         pytest.skip()
+
+
+@pytest.fixture()
+def skip_pre_python35(environment):
+    if environment.version_info < (3, 5):
+        # This if is just needed to avoid that tests ever skip way more than
+        # they should for all Python versions.
+        pytest.skip()

test/test_evaluate/test_signature.py

@@ -137,7 +137,7 @@ def test_tree_signature(Script, environment, code, expected):
         ('no_redirect(simple)', '*args, **kwargs'),
     ]
 )
-def test_nested_signatures(Script, environment, combination, expected):
+def test_nested_signatures(Script, environment, combination, expected, skip_pre_python35):
     code = dedent('''
         def simple(a, b, *, c): ...
         def simple2(x): ...