Avoiding TypeError when raw sql and no params

sql = u'SELECT (strftime(\'%Y%W\', datetime)) AS "week", AVG("core_expense"."amount") AS "average", SUM("core_expense"."amount") AS "total" FROM "core_expense" GROUP BY strftime(\'%Y%W\', datetime), (strftime(\'%Y%W\', datetime)) ORDER BY "week" ASC'

params = ()

When we try raw SQL queries like the one above, mainly when using builtin sql functions of the dbms, and devserver tries to print the queries, we get a "TypeError: not enough arguments for format string"