Function sp_finality_grandpa::sign_message

pub fn sign_message<H, N>(
    keystore: SyncCryptoStorePtr,
    message: Message<H, N>,
    public: AuthorityId,
    round: RoundNumber,
    set_id: SetId
) -> Option<SignedMessage<H, N, AuthoritySignature, AuthorityId>>where
    H: Encode,
    N: Encode,

Localizes the message to the given set and round and signs the payload.