method GenericExtrinsicPayload.prototype.signimport { GenericExtrinsicPayload } from "https://deno.land/x/polkadot@0.2.11/types/mod.ts"; sign(signerPair: IKeyringPair): { signature: HexString; }ParameterssignerPair: IKeyringPairReturns{ signature: HexString; }