code: def exclude(*args)
        e = flatten_list_of_strings(args)
        if e.nil? || e.empty?
          bot.exclude = []
        else
          bot.exclude += e
        end
      end
docs: specify list of strings we will check when deciding to respond
   to a tweet or not. accepts an array or a comma-delimited string.
   when called, any subsequent calls to search or replies will
   filter out tweets with these strings
  
   @param [Array, String] args list of usernames
   @example
     exclude "spam, junk, something"