in src/SignedSourceBase.hack [127:135]
public static function hasValidSignatureFromAnySigner(string $data): bool {
if (SignedSource::isSigned($data)) {
return SignedSource::verifySignature($data);
}
if (PartiallyGeneratedSignedSource::isSigned($data)) {
return PartiallyGeneratedSignedSource::verifySignature($data);
}
return false;
}