How to skip an element when iterating through a list Ruby

I have the following script which loops through an element list

    $browser.divs(class:'menu-index-page__menu-category').map do |cat|
  cate = cat.h3.text
  puts cate

  cc = cat.ul(class:'menu-index-page__items')
  cc.lis(class:'menu-index-page__item').each do |lit|
    lit.fire_event :click
    sleep(5)

however once in a while the name of the class list changes to:

menu-index-page__item menu-index-page__item--unavailable

This then breaks the script, I want to be able to skip this whenever is comes up and continue with the orginal script. Any help or pointers in the right direction would be greatly appreciated.