Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_25604014_4 (production_code VARCHAR, directed_by VARCHAR)

### Question ###
What is the production code for the episode directed by Sam weisman?

### Accurate SQL ###

SELECT production_code FROM table_25604014_4 WHERE directed_by = "Sam Weisman"