Replaced boolean test with is None
diff --git a/Lib/imputil.py b/Lib/imputil.py
index 65e799c..d83b16e 100644
--- a/Lib/imputil.py
+++ b/Lib/imputil.py
@@ -66,7 +66,7 @@
 
         # This is the Importer that we use for grabbing stuff from the
         # filesystem. It defines one more method (import_from_dir) for our use.
-        if not fs_imp:
+        if fs_imp is None:
             cls = self.clsFilesystemImporter or _FilesystemImporter
             fs_imp = cls()
         self.fs_imp = fs_imp