Update handler.py

handler.py

@@ -36,7 +36,7 @@ class Utterance:
         self.role = None
         self.word_count = self.get_num_words()
         self.timestamp = [starttime, endtime]
-        if starttime not None and endtime not None:                   
+        if starttime is not None and endtime is not None:                   
             self.unit_measure = endtime - starttime
         else:
             self.unit_measure = None