level: Set or get the priority level for a logger object.
Description
The priority level can be an integer from the set 1..5 (otherwise it will be
modified sensibly to fit in that range), or a named logging level (one of
"DEBUG", "INFO", "WARN", "ERROR", or "FATAL"). An object of class loglevel is
also accepted; other input will be coerced using as.loglevel().