Renaming a content file from .md to .html raises exception in serve mode

[yaph]

Error reading/parsing: content/index.md
[Errno 2] No such file or directory: 'content/index.md'
----------------------------------------
Exception happened during processing of request from ('127.0.0.1', 59798)
Traceback (most recent call last):
  File "/usr/lib/python3.8/socketserver.py", line 316, in _handle_request_noblock
    self.process_request(request, client_address)
  File "/usr/lib/python3.8/socketserver.py", line 347, in process_request
    self.finish_request(request, client_address)
  File "/usr/lib/python3.8/socketserver.py", line 360, in finish_request
    self.RequestHandlerClass(request, client_address, self)
  File "/home/.virtualenvs/logya/lib/python3.8/site-packages/logya-5.0.0-py3.8.egg/logya/server.py", line 19, in __init__
    super(HTTPRequestHandler, self).__init__(*args, directory=self.L.paths.public.as_posix())
  File "/usr/lib/python3.8/http/server.py", line 647, in __init__
    super().__init__(*args, **kwargs)
  File "/usr/lib/python3.8/socketserver.py", line 720, in __init__
    self.handle()
  File "/usr/lib/python3.8/http/server.py", line 427, in handle
    self.handle_one_request()
  File "/usr/lib/python3.8/http/server.py", line 415, in handle_one_request
    method()
  File "/home/.virtualenvs/logya/lib/python3.8/site-packages/logya-5.0.0-py3.8.egg/logya/server.py", line 22, in do_GET
    update_resource(self.path, self.L)
  File "/home/.virtualenvs/logya/lib/python3.8/site-packages/logya-5.0.0-py3.8.egg/logya/server.py", line 66, in update_resource
    if update_page(url, L):
  File "/home/.virtualenvs/logya/lib/python3.8/site-packages/logya-5.0.0-py3.8.egg/logya/server.py", line 33, in update_page
    L.update_collections(content['doc'])
  File "/home/.virtualenvs/logya/lib/python3.8/site-packages/logya-5.0.0-py3.8.egg/logya/core.py", line 82, in update_collections
    for attr, values in doc.copy().items():
AttributeError: 'NoneType' object has no attribute 'copy'