Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_77 (ppv_buyrate VARCHAR, date VARCHAR, event VARCHAR)
### Question:
On September 10 during Strikeforce: Heavyweight Grand Prix Semifinals, what was the PPV buyrate?
### Answer:
SELECT ppv_buyrate FROM table_name_77 WHERE date = "september 10" AND event = "strikeforce: heavyweight grand prix semifinals"