log_sql()
  SQL interscanner for python DB-API 2.0 compatible DB modules.
  
  Usage: log_sql(db_connection,format,scanners...)
         log_sql(...).also_clean()
  
  Where: db_connection is a database connection. For these connections
           see doc/Databases.txt file.
         format is a string, which defines an SQL INSERT command with
           optional variables described in log() scanner.
         .also_clean() can be used to log also "CLEAN" emails
  
  Examples: log_sql(DB_ENGINE, log_sql.FORMAT)
            log_sql(DB_ENGINE,
                    log_sql.FORMAT.extend('subject', '%(SUBJECT)s'))
  
  New in version 0.7.0.