def __init__(self, expires_at=None, **kwargs):
assert isinstance(expires_at, datetime) or expires_at is None<EOL>dt = expires_at - datetime.now() if expires_at else None<EOL>super(TimedSecretLinkSerializer, self).__init__(<EOL>current_app.config['<STR_LIT>'],<EOL>expires_in=int(dt.total_seconds()) if dt else None,<EOL>salt='<STR_LIT>',<EOL>**kwargs<EOL>)<EOL>
Initialize underlying TimedJSONWebSignatureSerializer.