def tree(self, tree_alias, context):
tree_alias, sitetree_items = self.init_tree(tree_alias, context)<EOL>if not sitetree_items:<EOL><INDENT>return '<STR_LIT>'<EOL><DEDENT>tree_items = self.filter_items(self.get_children(tree_alias, None), '<STR_LIT>')<EOL>tree_items = self.apply_hook(tree_items, '<STR_LIT>')<EOL>self.update_has_children(tree_alias, tree_items, '<STR_LIT>')<EOL>return tree_items<EOL>
Builds and returns tree structure for 'sitetree_tree' tag.

        :param str|unicode tree_alias:
        :param Context context:
        :rtype: list|str