code: def lookup_consumer(self, key):
          
          if not self.consumers:
              log.critical(("No consumers defined in settings."
                            "Have you created a configuration file?"))
              return None
  
          consumer = self.consumers.get(key)
          if not consumer:
              log.info("Did not find consumer, using key: %s ", key)
              return None
  
          secret = consumer.get('secret', None)
          if not secret:
              log.critical(('Consumer %s, is missing secret'
                            'in settings file, and needs correction.'), key)
              return None
          return oauth2.Consumer(key, secret)
docs: Search through keys