Fix README error handling example
Fix README error handling example

mspasov/KeychainAccess,kishikawakatsumi/KeychainAccess,colemancda/KeychainAccess,colemancda/KeychainAccess,ikesyo/KeychainAccess,sonsongithub/KeychainAccess,sonsongithub/KeychainAccess,ikesyo/KeychainAccess,sonsongithub/KeychainAccess,kishikawakatsumi/KeychainAccess,kishikawakatsumi/KeychainAccess,ikesyo/KeychainAccess,mspasov/KeychainAccess,colemancda/KeychainAccess