Returns root terms of the ontology. For some ontologies these functions might fail when the ontology used was not design to have root classes
返回根本体。对于某些本体,这些功能可能会失败时使用本体设计有根类
用法----------Usage----------
getRoots(object)
参数----------Arguments----------
参数:object
instance of the Ontology class
Ontology类的实例
值----------Value----------
Returns set of terms. Term in the set is the instance of OntologyTerm class
返回设置的条款。在设定的期限是OntologyTerm类的实例