still clinging to 3.9 compatibility

countess/plugins/python.py

@@ -1,7 +1,7 @@
 import builtins
 import math
 import re
-from types import BuiltinFunctionType, CodeType, FunctionType, ModuleType, NoneType
+from types import BuiltinFunctionType, CodeType, FunctionType, ModuleType
 from typing import Any
 
 import numpy as np
@@ -12,6 +12,9 @@
 from countess.core.parameters import BooleanParam, TextParam
 from countess.core.plugins import PandasTransformDictToDictPlugin
 
+# For 3.9 compatibility
+NoneType = type(None)
+
 # XXX pretty sure this is a job for ast.parse rather than just
 # running compile() and exec() but that can wait.
 # Builtins are restricted but there's still plenty of things which