# Functions
NewKeeper creates a new nft Keeper instance.
# Constants
StoreKey is the store key string for nft.
# Variables
ClassKey is store prefix of the Class.
ClassTotalSupply is store prefix of the ClassTotalSupply.
Delimiter is store key Delimiter.
NFTKey is store prefix of the NFT.
NFTOfClassByOwnerKey is store prefix of the NFTOfClassByOwner.
OwnerKey is store prefix of the Owner.
Placeholder is store key Placeholder.