CustomSource: {
    address: Address;
    signMessage: (({ message }) => Promise<Hash>);
    signTransaction: (<serializer, transaction>(transaction, args?) => Promise<IsNarrowable<TransactionSerialized<GetTransactionType<transaction>>, Hash> extends true
        ? TransactionSerialized<GetTransactionType<transaction>>
        : Hash>);
    signTypedData: (<const typedData, primaryType>(typedDataDefinition) => Promise<Hash>);
}

Type declaration