generateSeed(uint256) :
This function generates a random seed for a given nounId and descriptor. It does this by taking the keccak256 hash of the blockhash of the previous block and the nounId, and then using the resulting pseudorandomness to generate a seed with a background, body, accessory, head, and glasses. The seed is generated by taking the modulo of the pseudorandomness and the corresponding count for each item. (autogenerated documentation)