def printClassTree(self, element=None, showids=False, labels=False, showtype=False):
        """
        Print nicely into stdout the class tree of an ontology

        Note: indentation is made so that ids up to 3 digits fit in, plus a space.
        [123]1--
        [1]123--
        [12]12--
        """
        TYPE_MARGIN = 11  # length for owl:class etc..

        if not element:  # first time
            for x in self.toplayer_classes:
                printGenericTree(x, 0, showids, labels, showtype, TYPE_MARGIN)

        else:
            printGenericTree(element, 0, showids, labels, showtype, TYPE_MARGIN)
Print nicely into stdout the class tree of an ontology

        Note: indentation is made so that ids up to 3 digits fit in, plus a space.
        [123]1--
        [1]123--
        [12]12--