code: def convert_jwks_uri(jwks_uri):
    
    if not jwks_uri.startswith(_TEXT_CERT_PREFIX):
      return jwks_uri
    return jwks_uri.replace(_TEXT_CERT_PREFIX, _JSON_CERT_PREFIX)
docs: The PyCrypto library included with Google App Engine is severely limited and
    can't read X.509 files, so we change the URI to a special URI that has the
    public cert in modulus/exponent form in JSON.