tokens: So , unlike other languages , where A IS-A String is represented by A being a subclass of String , in Ruby , the relationship A IS-A String is represented by A having a to_str method .
ner_tags: O O O O O O O B-Value I-Value I-Value O O O B-Class O O O O B-Data_Type O O B-Language O O O B-Value I-Value I-Value O O O B-Class O O B-Function O O