[python] remove TODO and use Dynamic for now

std/python/lib/ThreadLowLevel.hx

@@ -23,11 +23,9 @@ package python.lib;
 
 import python.Tuple;
 
-private typedef TODO = Dynamic;
-
 @:pythonImport("_thread")
 extern class ThreadLowLevel {
 
-	public static function start_new_thread(f:Void->Void, args:Tuple<Dynamic>):TODO;
+	public static function start_new_thread(f:Void->Void, args:Tuple<Dynamic>):Dynamic;
 
 }