@catch_nb_assignment<EOL><INDENT>def cell_exception(self, cell, cell_index=None, **kwargs):<DEDENT>
cell.metadata.papermill['<STR_LIT>'] = True<EOL>cell.metadata.papermill['<STR_LIT:status>'] = self.FAILED<EOL>self.nb.metadata.papermill['<STR_LIT>'] = True<EOL>
Set metadata when an exception is raised.

Called by engines when an exception is raised within a notebook to
set the metadata on the notebook indicating the location of the
failure.