/Users/simon/.local/share/virtualenvs/datasette-AWNrQs95/lib/python3.10/site-packages/jinja2/loaders.py:200: in get_source
    f = open_if_exists(filename)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

filename = '/Users/simon/Dropbox/Development/datasette/datasette/templates/error.html', mode = 'rb'

    def open_if_exists(filename: str, mode: str = "rb") -> t.Optional[t.IO]:
        """Returns a file descriptor for the filename if that file exists,
        otherwise ``None``.
        """
        if not os.path.isfile(filename):
            return None
    
>       return open(filename, mode)
E       OSError: [Errno 24] Too many open files: '/Users/simon/Dropbox/Development/datasette/datasette/templates/error.html'