Net::Amazon::Validate::ItemSearch::us::Keywords - valid search indicies for the
us locale and the Keywords SearchIndex.
The default value is Books, unless mode is specified.
The list of available values are:
Apparel
Automotive
Baby
Beauty
Blended
Books
Classical
DVD
DigitalMusic
Electronics
GourmetFood
HealthPersonalCare
HomeGarden
Industrial
Jewelry
KindleStore
Kitchen
Magazines
Merchants
Miscellaneous
Music
MusicTracks
MusicalInstruments
OfficeProducts
OutdoorLiving
PCHardware
PetSupplies
Photo
Shoes
SilverMerchants
Software
SportingGoods
Tools
Toys
UnboxVideo
VHS
Video
VideoGames
Watches
Wireless
WirelessAccessories