Query a given storage key in a given contract.
Returns Ok(Some(Vec<u8>)) if the storage value exists under the given key in the specified account and Ok(None) if it doesn't. If the account specified by the address doesn't exist, or doesn't have a contract then Err is returned.
Ok(Some(Vec<u8>))
Ok(None)
Err
Query a given storage key in a given contract.
Returns
Ok(Some(Vec<u8>))
if the storage value exists under the given key in the specified account andOk(None)
if it doesn't. If the account specified by the address doesn't exist, or doesn't have a contract thenErr
is returned.