NIP-07 global Window interface, signEvent returns string instead of event?

[neilck]

In signers/nip07/index.ts

declare global {
    interface Window {
        nostr?: {
            ...
            signEvent(event: NostrEvent): Promise<{ sig: string }>;
    ...

According to NIP-07 I think it should return an event instead of a string? signEvent(event: NostrEvent): Promise<{ sig: NostrEvent }>;