code: def unix_time(self, end_datetime=None, start_datetime=None):
          
          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)
docs: Get a timestamp between January 1, 1970 and now, unless passed
          explicit start_datetime or end_datetime values.
          :example 1061306726