European Union (Notification of Withdrawal) Act 2017

You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10.

# Requirements
- If you don't know the subject at all, return an empty list.
- If the subject is not a named entity, return an empty list.
- Include at least one triple where predicate is "instanceOf".
- Do not get too wordy.
- Separate several objects into multiple triples with one object.

Subject: European Union (Notification of Withdrawal) Act 2017
Description of subject: The European Union (Notification of Withdrawal) Act 2017 is a UK law that authorized the Prime Minister to formally trigger Article 50 of the Treaty on European Union, beginning the legal process of the United Kingdom’s withdrawal from the EU.