title: Incoming SMS with Python SMPP
body: <p>I'm an new to using SMPP. I am not quite sure incoming messages works. I am implementing this in Python 2.7 using smpplib.I was able to connect to the SMPP service and send out SMS using a bind_transmitter.</p>
  
  <p>In the example there is a function call recv_handler, however I don't see it call for anywhere. Here is the function:</p>
  
  <pre><code>    def recv_handler(self, **args):
          print 'Message received:', args
  </code></pre>
  
  <p>Any help would be great. Thank you.</p>