@Override
        public List<ValidationEvent> validateScheme(
                Map<Identifier, Literal> authScheme,
                FromSourceLocation sourceLocation,
                BiFunction<FromSourceLocation, String, ValidationEvent> emitter
        ) {
            List<ValidationEvent> events = noExtraProperties(emitter,
                    sourceLocation,
                    authScheme,
                    ListUtils.of(RuleSetAuthSchemesValidator.NAME,
                            ID_SIGNING_NAME,
                            ID_SIGNING_REGION,
                            ID_DISABLE_DOUBLE_ENCODING,
                            ID_DISABLE_NORMALIZE_PATH));

            // Validate shared Sigv4 properties.
            events.addAll(SigV4SchemeValidator.validateOptionalSharedProperties(authScheme, emitter));
            // Signing region is also optional.
            if (authScheme.containsKey(ID_SIGNING_REGION)) {
                validateStringProperty(emitter, authScheme, ID_SIGNING_REGION).ifPresent(events::add);
            }
            return events;
        }
Returns if a given auth scheme is equivalent to {@code aws.auth#sigv4a}.

@param authScheme name of the auth scheme.
@return whether the auth scheme is equivalent to {@code aws.auth#sigv4a}.
smithy-aws-endpoints/src/main/java/software/amazon/smithy/rulesengine/aws/language/functions/EndpointAuthUtils.java