code: def get_s3_uri(m, file_names, config):
      
      bucket_name = m.group(1)
      path = m.group(2)
      bucket = get_s3_bucket(bucket_name, config)
      result = 0
      if (config.start_date or config.date_range) and ("{year" in path or "{month" in path or "{day" in path):
          for tmp_date in date_generator(config.end_date, config.date_range or ((config.end_date - config.start_date).days + 1)):
              # +1 because we want to include end_date
              for key in bucket.list(prefix=path.format(year=tmp_date.year, month=tmp_date.month, day=tmp_date.day)):
                  file_names.append("s3://{}/{}".format(bucket_name, key.name))
                  result += key.size
      else:
          for key in bucket.list(prefix=path):
              file_names.append("s3://{}/{}".format(bucket_name, key.name))
              result += key.size
      return result
docs: populates file_names list with urls that matched the regex match object
      returns the total filesize of all the files matched