def is_show_uncategorized(self, request):
        """Return the result of the "?show_uncategorized" query string param"""

        show_uncategorized = request.GET.get('show_uncategorized', False)
        if show_uncategorized is True or show_uncategorized == 'true':
            return True
        return False
def dfs_print(root):
        if root is None:
            return
        dfs_print(root.left)
        print(str(root.key) + ' ', end='')
        dfs_print(root.right)