def prune_empty_groups
      @channels.each_value do |channel|
        channel.leave_group if channel.group? && channel.recipients.empty?
      end
    end
def prune_empty_groups
      @channels.each_value do |channel|
        channel.leave_group if channel.group? && channel.recipients.empty?
      end
    end
Makes the bot leave any groups with no recipients remaining