protected void doInsert(String permission) {
        permission = permission.toLowerCase(Locale.ROOT);

        // split the permission up into parts
        Iterable<String> parts = DOT_SPLIT.split(permission);

        // insert the permission into the node structure
        TreeNode current = this.rootNode;
        for (String part : parts) {
            current = current.tryInsert(part);
            if (current == null) {
                return;
            }
        }
    }
Insert a permission into the registry.

@param permission the permission
common/src/main/java/me/lucko/luckperms/common/treeview/PermissionRegistry.java