def growl_level_num( level )
      level = Integer(level)
      if level < -2 or level > 2
        raise ArgumentError, "level '#{level}' is not in range -2..2"
      end
      level
    end
def growl_level_num( level )
      level = Integer(level)
      if level < -2 or level > 2
        raise ArgumentError, "level '#{level}' is not in range -2..2"
      end
      level
    end
call-seq:
    growl_level_num( level )    => integer

 Takes the given _level_ as a string or integer and returns the
 corresponding Growl notification level number.