Just for fun, for now:
debug!("This is a debug message.");
info!("This is an info message.");
warn!("This is a warning message.");
error!("This is an error message.");
critical!("This is a critical message.");
Program Log: [DEBUG]: This is a debug message.
Program Log: [INFO]: This is an info message.
Program Log: [WARN]: This is a warning message.
Program Log: [ERROR]: This is an error message.
Program Log: [CRITICAL]: This is a critical message.