Run collection stats for collection.
        see https://docs.mongodb.com/manual/reference/command/collStats/

        :param scale: Scale at which to report sizes
        :param verbose: used for extended report on legacy MMAPV1 storage engine
        :return: JSON doc with stats

def collstats(self, scale=1024, verbose=False):
        """
        Run collection stats for collection.
        see https://docs.mongodb.com/manual/reference/command/collStats/

        :param scale: Scale at which to report sizes
        :param verbose: used for extended report on legacy MMAPV1 storage engine
        :return: JSON doc with stats
        """
        self.print_doc(self.database.command(
                            {"collStats": self._collection_name,
                             "scale": scale,
                             "verbose": verbose}))