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_29087004_2 (written_by VARCHAR, united_states_original_airdate VARCHAR, directed_by VARCHAR, canada_original_airdate VARCHAR)
### Question:
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?
### Answer:
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"