docs: def to_string(level):
          """
          Converts log level to a string.
  
          :param level: a log level to convert
  
          :return: log level name string.
          """
          if level == LogLevel.Fatal:
              return "FATAL" 
          if level == LogLevel.Error:
              return "ERROR" 
          if level == LogLevel.Warn:
              return "WARN" 
          if level == LogLevel.Info:
              return "INFO" 
          if level == LogLevel.Debug:
              return "DEBUG" 
          if level == LogLevel.Trace:
              return "TRACE"
          return "UNDEF"