public LiteralExpression getObjectField(String name) {
        Map<String, Object> values = expectObjectValue();
        return values.containsKey(name)
                ? new LiteralExpression(values.get(name))
                : new LiteralExpression(null);
    }
Expects the value to be an object and gets a field by
name. If the field does not exist, then a
{@link LiteralExpression} with a null value is returned.

@param name Field to get from the expected object.
@return Returns the object field value.
smithy-jmespath/src/main/java/software/amazon/smithy/jmespath/ast/LiteralExpression.java