Add an enumeration for log levels?

[mikeckennedy]

Hi folks. I'm a big fan of this library! But I always end up creating something to store the log levels in a reliable way. I'd like to write code like this, using a clear class offering autocomplete (potentially docstrings, etc):

Then we can use it like:

logbook.StreamHandler(sys.stdout, level=LogLevel.debug).push_application()

And the LogLevel class is a collection like this with a nice parse option for verification and canonicalization (e.g. "error " --> "ERROR"):

class LogLevel:
    debug = "DEBUG"
    info = "INFO"
    notice = "NOTICE"
    warning = "WARNING"
    error = "ERROR"
    critical = "CRITICAL"

    @staticmethod
    def parse(level_text: str) -> str:
        if not level_text:
            raise Exception("Level text must be specified")

        level_text = level_text.upper().strip()

        if level_text == LogLevel.debug:
            return LogLevel.debug
        elif level_text == LogLevel.info:
            return LogLevel.info
        elif level_text == LogLevel.notice:
            return LogLevel.notice
        elif level_text == LogLevel.warning:
            return LogLevel.warning
        elif level_text == LogLevel.error:
            return LogLevel.error
        elif level_text == LogLevel.critical:
            return LogLevel.critical
        else:
            raise Exception(f"The level text {level_text} is not a supported log level.")

Would you be willing to adopt something like this?