[pitivi] Interpolator: check keyword arguments against None, not falsehood

[Edward Hervey <edwardrv src gnome org>]

commit 3d9f35ca13db0f921d0fcc61010de30d7ef59de2
Author: Brandon Lewis <brandon_lewis berkeley edu>
Date:   Wed Jun 24 21:25:55 2009 -0700

    Interpolator: check keyword arguments against None, not falsehood

 pitivi/timeline/track.py |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/pitivi/timeline/track.py b/pitivi/timeline/track.py
index 9e1ccbf..8d66148 100644
--- a/pitivi/timeline/track.py
+++ b/pitivi/timeline/track.py
@@ -175,9 +175,9 @@ class Interpolator(Signallable, Loggable):
         self.debug("time:%s, value:%r, mode:%r",
                    gst.TIME_ARGS(time), value, mode)
         #TODO: calculate value
-        if not value:
+        if value is None:
             value = self._default
-        if not mode:
+        if mode is None:
             # FIXME: uncomment this when back-end support works
             #mode = self._controller.get_interpolation_mode()
             mode = gst.INTERPOLATE_LINEAR