Returns the dependency path from the term to the root
        @type termid: string
        @param termid: the term identifier
        @rtype: list
        @return: list of dependency relations

def get_path_to_root(self,termid):
        """
        Returns the dependency path from the term to the root
        @type termid: string
        @param termid: the term identifier
        @rtype: list
        @return: list of dependency relations
        """        
        # Get the sentence for the term
        root = None
        sentence = self.sentence_for_termid.get(termid)
        
        if sentence is None:    #try with the top node
            top_node = self.top_relation_for_term.get(termid)
            if top_node is not None:
                root = top_node[1]
            else:
                return None
        else:
            if sentence in self.root_for_sentence:
                root = self.root_for_sentence[sentence]
            else:
                ##There is no root for this sentence
                return None
        # In this point top_node should be properly set
        path = self.get_shortest_path(termid, root)
        return path