py3: update all the things

Change-Id: I5e11b46b7c2f7f8760d6c0e713ca99c1e88b7cd3
diff --git a/tools/releasetools/rangelib.py b/tools/releasetools/rangelib.py
index 373bbed..cbb34b9 100644
--- a/tools/releasetools/rangelib.py
+++ b/tools/releasetools/rangelib.py
@@ -43,6 +43,8 @@
     return self.data != other.data
   def __nonzero__(self):
     return bool(self.data)
+  def __bool__(self):
+    return self.__nonzero__()
 
   def __str__(self):
     if not self.data: