class Sanitize::CSS

def import_url_allowed?(rule)
  return true unless @import_url_validator
  url_token = rule[:tokens].detect { |t| t[:node] == :url || t[:node] == :string }
  # don't allow @imports with no URL value
  return false unless url_token && (import_url = url_token[:value])
  @import_url_validator.call(import_url)
end