Function verify 

pub fn verify(
    attachment: &RootAttachment,
    original_credential: &[u8],
    trusted_roots: &[PublicKey],
    expected_account_id: &str,
    expected_device: &EndpointRef,
    now: DateTime<Utc>,
) -> Result<VerifiedAttachment, Error>

trusted_roots must be independently attached to expected_account_id. The binding never supplies its own trust list or authorizes a future call.