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 weather (zip_code VARCHAR, max_dew_point_f VARCHAR)
### Question:
Find all the zip codes in which the max dew point have never reached 70.
### Answer:
SELECT DISTINCT zip_code FROM weather EXCEPT SELECT DISTINCT zip_code FROM weather WHERE max_dew_point_f >= 70