basic python 3.9 support

testenv/linters/mypy.ini

@@ -1,5 +1,5 @@
 [mypy]
-python_version = 3.8
+python_version = 3.9
 ignore_missing_imports = true
 disallow_untyped_defs = true
 strict_optional = true

testenv/linters/pylint.ini

@@ -34,6 +34,8 @@ disable =
 	len-as-condition,
 	raise-missing-from,
 	consider-using-in,
+	unsubscriptable-object,
+# https://github.com/PyCQA/pylint/issues/3882
 
 [CLASSES]
 exclude-protected =