no return events in call

app/cel.py

@@ -47,6 +47,8 @@ class CdrEvents:
       event = CdrEvent(event)
     if not self.start:
         self.start = event.calldate
+    if (event.lastapp == 'Return'):
+      return
     if (event.channel.id not in self._channels):
         self._channels[event.channel.id] = event
     if (event.dstchannel.id not in self._dstchannels):