old_contents: from urllib import urlencode
  from urllib2 import urlopen
  
  from rapidsms.backends.base import BackendBase
  
  class TropoBackend(BackendBase):
      """A RapidSMS threadless backend for Tropo"""
  
     def configure(self, config=None, **kwargs):
          self.config = config
          super(TropoBackend, self).configure(**kwargs)
          
     def send(self, message):
          base_url = 'http://api.tropo.com/1.0/sessions'
          token = self.config['auth_token']
          action = 'create'
          number = self.config['number']
  
          params = urlencode([('action', action), ('token', token), ('numberToDial', message.connection.identity), ('msg', message.text)])
          self.debug("%s?%s" % (base_url, params))
          data = urlopen('%s?%s' % (base_url, params)).read()
          self.debug(data)
  
new_contents: from urllib import urlencode
  from urllib2 import urlopen
  
  from rapidsms.backends.base import BackendBase
  
  class TropoBackend(BackendBase):
      """A RapidSMS threadless backend for Tropo"""
  
      def configure(self, config=None, **kwargs):
          self.config = config
          
      def start(self):
          """Override BackendBase.start(), which never returns"""
          self._running = True
  
      def send(self, message):
          self.debug("send(%s)" % message)
          base_url = 'http://api.tropo.com/1.0/sessions'
          token = self.config['auth_token']
          action = 'create'
          number = self.config['number']
  
          params = urlencode([('action', action), ('token', token), ('numberToDial', message.connection.identity), ('msg', message.text)])
          self.debug("%s?%s" % (base_url, params))
          data = urlopen('%s?%s' % (base_url, params)).read()
          self.debug(data)
          return True
  
subject: Fix indentation; override old-style start() from BackendBase