raise_for_status

def raise_for_status(self):
    """Raises stored :class:`HTTPError`, if one occurred."""
    http_error_msg = ""

    if isinstance(self.reason, bytes):
        # We attempt to decode utf-8 first because some servers
        # choose to localize their reason strings. If the string
        # isn't utf-8, we fall back to iso-8859-1 for all other
        # encodings. (See PR #3538)
        try:
            reason = self.reason.decode('utf-8')
        except UnicodeDecodeError:
            reason = self.reason.decode('iso-8859-1')
    else:
        reason = self.reason

    if 400 <= self.status_code < 500:
        http_error_msg = u'%s Client Error: %s for url: %s' % (self.status_code, reason, self.url)

    elif 500 <= self.status_code < 600:
        http_error_msg = u'%s Server Error: