Who wrote the episode directed by Jos Humphrey that had an original Canadian air date that was unknown and a United States original air date of August 27, 2011?
CREATE TABLE table_29087004_2 (
    written_by VARCHAR,
    united_states_original_airdate VARCHAR,
    directed_by VARCHAR,
    canada_original_airdate VARCHAR
)
SELECT written_by FROM table_29087004_2 WHERE directed_by = "Jos Humphrey" AND canada_original_airdate = "Unknown" AND united_states_original_airdate = "August 27, 2011"
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: Who wrote the episode directed by Jos Humphrey that had an original Canadian air date that was unknown and a United States original air date of August 27, 2011? ### Input: CREATE TABLE table_29087004_2 (
    written_by VARCHAR,
    united_states_original_airdate VARCHAR,
    directed_by VARCHAR,
    canada_original_airdate VARCHAR
) ### Response: SELECT written_by FROM table_29087004_2 WHERE directed_by = "Jos Humphrey" AND canada_original_airdate = "Unknown" AND united_states_original_airdate = "August 27, 2011"