def visit_classdef(self, node):
        """visit an astroid.Class node

         * set the locals_type and instance_attrs_type mappings
         * set the implements list and build it
         * optionally tag the node with a unique id
        """
        if hasattr(node, "locals_type"):
            return
        node.locals_type = collections.defaultdict(list)
        if self.tag:
            node.uid = self.generate_id()
        # resolve ancestors
        for baseobj in node.ancestors(recurs=False):
            specializations = getattr(baseobj, "specializations", [])
            specializations.append(node)
            baseobj.specializations = specializations
        # resolve instance attributes
        node.instance_attrs_type = collections.defaultdict(list)
        for assignattrs in node.instance_attrs.values():
            for assignattr in assignattrs:
                self.handle_assignattr_type(assignattr, node)
        # resolve implemented interface
        try:
            node.implements = list(interfaces(node, self.inherited_interfaces))
        except astroid.InferenceError:
            node.implements = ()