query() method sends a SQL query to the database. If the query is an insert statement, the return value is the OID of the newly inserted row. If it is otherwise a query that does not return a result (i.e., is not a some kind of SELECT statement), it returns None. Otherwise, it returns a pgqueryobject that can be accessed via the getresult() or dictresult() methods or simply printed.
If you see anything in the documentation that is not correct, does not match your experience with the particular feature or requires further clarification, please use this form to report a documentation issue.