code: def channels_list(self, exclude_archived=True, **params):
          
          method = 'channels.list'
          params.update({'exclude_archived': exclude_archived and 1 or 0})
          return self._make_request(method, params)
docs: channels.list
  
          This method returns a list of all channels in the team. This includes
          channels the caller is in, channels they are not currently in, and
          archived channels. The number of (non-deactivated) members in each
          channel is also returned.
  
          https://api.slack.com/methods/channels.list