gistfile1.rb

module Filter

  FILTERS = {
    :not_cancelled => lambda {|booking| booking.cancelled == false },
    # ...
  }

  def filter(rows, *filters)
    booking = Booking.get_in_class(row['booking_reference'])
    is_ok = true
    filters.each do |filter_name|
      if FILTERS.keys.include?(filter_name)
        is_ok = is_ok && Filter::FILTERS[filter][booking] 
        #pick it up and call it
      elsif filter_name.kind_of?(Proc)
        is_ok = is_ok && filter_name[booking]
        # you could also supply your own filter | probably not needed at all
      else raise 'Error! Could not find filter'
      end
    end
    is_ok
  end

end

# filter(rows, :not_canceled, :not_working, :not_booked, :not_nuked)

added checkup of filter in FILTERS