code: def ip_addresses_from_xff(value: str) -> List[str]:
      
      if not value:
          return []
      return [x.strip() for x in value.split(",")]
docs: Returns a list of IP addresses (as strings), given the value of an HTTP
      ``X-Forwarded-For`` (or ``WSGI HTTP_X_FORWARDED_FOR``) header.
  
      Args:
          value:
              the value of an HTTP ``X-Forwarded-For`` (or ``WSGI
              HTTP_X_FORWARDED_FOR``) header
  
      Returns:
          a list of IP address as strings
  
      See:
      - https://en.wikipedia.org/wiki/X-Forwarded-For
      - https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For  # noqa
      - NOT THIS: http://tools.ietf.org/html/rfc7239