tokens: After all , the Quaternion class did n't exist when the Fixnum class was written , so the Fixnum class cannot know about Quaternions . But when the Quaternion class was written , maybe the author was so thoughtful to make it possible to compare Quaternions with Fixnums .
ner_tags: O O O O B-Class O O O O O O B-Class O O O O O O B-Class O O O O B-Class O O O O B-Class O O O O O O O O O O O O O O O O B-Class O B-Class O