user: Question: What is the production code directed by Matt Shakman?
Columns: ['No. in Series', 'No. in Season', 'Title', 'Directed by', 'Written by', 'Original air date', 'Production code', 'U.S. viewers (millions)']
Types: ['real', 'real', 'text', 'text', 'text', 'text', 'real', 'text']
Sample row: [24.0, 1.0, '"Home Front"', 'Ken Olin', 'Monica Owusu-Breen & Alison Schapker', 'September30,2007', 201.0, '13.26']
SQL:

assistant: SELECT "Production code" FROM "Table" WHERE "Directed by" = 'Matt Shakman';