private List<ValidationEvent> hasAllKeys(
                BiFunction<FromSourceLocation, String, ValidationEvent> emitter,
                Map<Identifier, Literal> authScheme,
                List<Identifier> requiredKeys,
                FromSourceLocation sourceLocation
        ) {
            List<ValidationEvent> events = new ArrayList<>();
            for (Identifier key : requiredKeys) {
                if (!authScheme.containsKey(key)) {
                    emitter.apply(sourceLocation, String.format("Missing key: `%s`", key));
                }
            }
            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