How to solve Failed to run “xelatex .notebook.tex -quiet” command: notebook.tex:373:?

I am trying to convert my jupyterlab into pdf but I am getting this error server.

nbconvert failed: PDF creating failed, captured latex output: Failed
to run "xelatex .notebook.tex -quiet" command: notebook.tex:373:

and here is the code that I am using:

documentclass{article}
begin{documentation}
begin{equation}
  f(x) = x^2
end{equation}
end{documentation}

I want to precise that I have downloaded all the updates in MikTeX, and the same code without document… & begin… & end… works fine. I also tried to change the location of end by placing it at the end of the fist block, and it’s still giving me the same error.

PS: nbconvert Convert Notebooks to other formats.
Can anyone help please?