SET TIME ZONE :tz - syntax error at or near "$1"

This might end up being an asyncpg question, but I’m getting an error when I run
await database.execute(query=“SET TIME ZONE :tz”, values={‘tz’: ‘UTC’})

The error looks a lot like others I have seen when I didn’t have the type correct for my values dict
PostgresSyntaxError: syntax error at or near “$1”

According to the postgresql docs the type I should be using is a string

UPDATE:
It appears this won’t work anyways, if I hard code “SET TIME ZONE ‘UTC’” it doesn’t take effect in the following queries like it does when I was on psycopg2. Looks like a session scope thing.

Anyone else hit this problem or have any ideas?