human
Considering the provided database schema and associated query, produce SQL code to retrieve the answer to the query. 
###Database Schema: No. in series, No. in season, Title, Directed by, Written by, Original air date, Production code, U.S. viewers (millions)
###Question: when the writer is Brad Kern, how many u.s viewers (in millions) had the episode?
gpt
SELECT U.S. viewers (millions) FROM table WHERE Written by = Brad Kern