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_10 (source VARCHAR, net_worth_us$__billions_ VARCHAR)
### Question:
What's the source of wealth of the person worth $17 billion?
### Answer:
SELECT source FROM table_name_10 WHERE net_worth_us$__billions_ = 17