Cannot run fastapi multi apps example

I cannot run the multi-app example found here.

I receive this error

File “\lib\site-packages\panel\io___templates\index_html.generated.py”, line 5, in _tt_execute
_tt_tmp = base_url|default("", true) # \lib\site-packages\panel\io…_templates\index.html:23
NameError: name ‘base_url’ is not defined
500 GET / (127.0.0.1) 6.98ms