code: def _annotate(
          cls,
          item,
          timestamp,
          stack_depth
      ):
          
          item.timestamp = timestamp
          item.machine = machine_metadata
          item.template = strings.limit(item.template, 10000)
  
          item.format = strings.limit(item.format, 10000)
          if item.format == None:
              format = text_type(item)
          else:
              format = item.format.replace("{{", "{{params.")
          if not format.startswith(CR) and format.find(CR) > -1:
              format = CR + format
  
          if cls.trace:
              log_format = item.format = "{{machine.name}} (pid {{machine.pid}}) - {{timestamp|datetime}} - {{thread.name}} - \"{{location.file}}:{{location.line}}\" - ({{location.method}}) - " + format
              f = sys._getframe(stack_depth + 1)
              item.location = {
                  "line": f.f_lineno,
                  "file": text_type(f.f_code.co_filename),
                  "method": text_type(f.f_code.co_name)
              }
              thread = _Thread.current()
              item.thread = {"name": thread.name, "id": thread.id}
          else:
              log_format = item.format = "{{timestamp|datetime}} - " + format
  
          cls.main_log.write(log_format, item.__data__())
docs: :param itemt:  A LogItemTHE TYPE OF MESSAGE
          :param stack_depth: FOR TRACKING WHAT LINE THIS CAME FROM
          :return: