get it building w/python3

--- a/setup.py
+++ b/setup.py
@@ -18,11 +18,11 @@ def fixso(filepath):
 class my_build_ext(build_ext):
     def build_extension(self, ext):
         sources = ext.sources
-        if sources is None or type(sources) not in (ListType, TupleType):
-            raise DistutilsSetupError, \
+        if sources is None or not isinstance(sources, (list, tuple)):
+            raise DistutilsSetupError(
                   ("in 'ext_modules' option (extension '%s'), " +
                    "'sources' must be present and must be " +
-                   "a list of source filenames") % ext.name
+                   "a list of source filenames") % ext.name)
         sources = list(sources)
         fullname = self.get_ext_fullname(ext.name)
         if self.inplace: