user: Question: Name the total number of production code for  episode by Steve Cohen & Andrew Dettman
Columns: ['No.', '#', 'Title', 'Directed by', 'Written by', 'U.S. viewers (million)', 'Original air date', 'Production code']
Types: ['real', 'real', 'text', 'text', 'text', 'text', 'text', 'real']
Sample row: [62.0, 1.0, '" Trust Metric "', 'Tony Scott', 'Ken Sanzel', '9.38', 'September28,2007', 401.0]
SQL:

assistant: SELECT COUNT("Production code") FROM "Table" WHERE "Written by" = 'Steve Cohen & Andrew Dettman';