method keyring.Keyring.prototype.addFromMnemonicimport { keyring } from "https://dotland.deno.dev/x/polkadot@0.2.38/mod.ts"; const { Keyring } = keyring; addFromMnemonic(mnemonic: string,meta?: KeyringPair$Meta,type?: KeypairType,): KeyringPairParametersmnemonic: stringoptionalmeta: KeyringPair$Meta = [UNSUPPORTED]optionaltype: KeypairType = [UNSUPPORTED]ReturnsKeyringPair