CKEY_BLACKLIST = [
  # non-book ckeys
  '2650945',
  '2911666',
  '2911781',
  '2912857',
  '2914708',
  '6828286',
  '7164326',
  '7164327',
  '7907729',
  '8596214',
  '8830687',
  '9144273',
  '9347773',
  '10415691',
  '10576418',
  '10578389',
  '10586419',
  '10727639',
  '10785585',
  '10947648',
  '11624628',
  '11624640',
  '11651132',
  '11682224',
  '11743826',
  '11874840',
  '15007992'
].freeze
