@property<EOL><INDENT>def url(self):<DEDENT>
if self._url is not None:<EOL><INDENT>url = self._url<EOL><DEDENT>else:<EOL><INDENT>url = getattr(self.nb.metadata, '<STR_LIT:url>', None)<EOL><DEDENT>if url is not None:<EOL><INDENT>return nbviewer_link(url)<EOL><DEDENT>
The url on jupyter nbviewer for this notebook or None if unknown