generated StorageKey not right for System.Account(AccountId)

[tarvos21]

Hi, I try to generate the StorageKey for an accountId at System module Account method.

The result is shorter than the items returned from getKeys(), 32 characters shorter precisly.

I want to get the account info and balance in the history blocks, and then I encounter the problem.

And any example to decode the result from getStorage? For example, the api.query.system.account storage.

Thanks!