docs: def _get_host(self, region):
          """
          Returns correctly formatted host. Accepted formats:
  
              * simple region name, eg 'us-west-1' (see list in AWS_REGIONS)
              * full host name, eg 's3-us-west-1.amazonaws.com'.
          """
          if 'us-east-1' in region:
              return 's3.amazonaws.com'
          elif region in AWS_REGIONS:
              return 's3-%s.amazonaws.com' % region
          elif region and not REGION_RE.findall(region):
              raise ImproperlyConfigured('AWS_REGION improperly configured!')
          # can be full host or empty string, default region
          return  region