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_1337525_1 ( region_4 VARCHAR, complete_series VARCHAR )

### Question ###
What is the number of region 4 for the series of the complete seventh series?

### Accurate SQL ###

SELECT COUNT(region_4) FROM table_1337525_1 WHERE complete_series = "The Complete Seventh Series"