What is the average number of players who play my game daily?

SELECT AVG(_users) AS  DAU
FROM (
            SELECT _day, COUNT(internal_user_id) AS _users 
            FROM (
                        SELECT date(event_time_ts) AS _day, internal_user_id 
                        FROM cooladata
                        WHERE date_range(doc.date_range)  
                       and doc.slicers
                        GROUP BY _day, internal_user_id 
            )
            GROUP BY _day 
)