(self, sub_docnum)
Returns a sorting key for the current match. This should return the
        same value returned by :meth:`Collector.collect`, but without the side
        effect of adding the current document to the results.

        If the collector has been prepared with ``context.needs_current=True``,
        this method can use ``self.matcher`` to get information, for example
        the score. Otherwise, it should only use the provided ``sub_docnum``,
        since the matcher may be in an inconsistent state.

        Subclasses must implement this method.
Returns a sorting key for the current match. This should return the
        same value returned by :meth:`Collector.collect`, but without the side
        effect of adding the current document to the results.
Returns a sorting key for the current match . This should return the same value returned by : meth : Collector . collect but without the side effect of adding the current document to the results .
def sort_key(self, sub_docnum):
        """Returns a sorting key for the current match. This should return the
        same value returned by :meth:`Collector.collect`, but without the side
        effect of adding the current document to the results.

        If the collector has been prepared with ``context.needs_current=True``,
        this method can use ``self.matcher`` to get information, for example
        the score. Otherwise, it should only use the provided ``sub_docnum``,
        since the matcher may be in an inconsistent state.

        Subclasses must implement this method.
        """

        raise NotImplementedError
def sort_key ( self , sub_docnum ) : raise NotImplementedError