def validate_is_non_abstract_vertex_type(self, vertex_classname):
        """Validate that a vertex classname corresponds to a non-abstract vertex class."""
        element = self.get_vertex_schema_element_or_raise(vertex_classname)

        if element.abstract:
            raise InvalidClassError(u'Expected a non-abstract vertex class, but {} is abstract'
                                    .format(vertex_classname))
Validate that a vertex classname corresponds to a non-abstract vertex class.