def ontologyConceptTree(self):
        """
        Returns a dict representing the skos tree
        Top level = {0:[top concepts]}
        Multi inheritance is represented explicitly
        """
        treedict = {}
        if self.all_skos_concepts:
            treedict[0] = self.toplayer_skos
            for element in self.all_skos_concepts:
                if element.children():
                    treedict[element] = element.children()
            return treedict
        return treedict
Returns a dict representing the skos tree
        Top level = {0:[top concepts]}
        Multi inheritance is represented explicitly