def unix_time(self, end_datetime=None, start_datetime=None):
        """
        Get a timestamp between January 1, 1970 and now, unless passed
        explicit start_datetime or end_datetime values.
        :example 1061306726
        """
        start_datetime = self._parse_start_datetime(start_datetime)
        end_datetime = self._parse_end_datetime(end_datetime)
        return self.generator.random.randint(start_datetime, end_datetime)