code: def chime_sender(webhook_url: str, user_mentions: List[str] = []):
      """
      Chime sender wrapper: execute func, send a chime notification with the end status
      (successfully finished or crashed) at the end. Also send a Chime notification before
      executing func.
  
      `webhook_url`: str
          The webhook URL to access your chime room.
          Visit https://docs.aws.amazon.com/chime/latest/dg/webhooks.html for more details.
      `user_mentions`: List[str] (default=[])
          Optional users alias or full email address to notify.
      """
  
      dump = {}
  
      def decorator_sender(func):
          @functools.wraps(func)
          def wrapper_sender(*args, **kwargs):
              start_time = datetime.datetime.now()
              host_name = socket.gethostname()
              func_name = func.__name__
  
              # Handling distributed training edge case.
              # In PyTorch, the launch of `torch.distributed.launch` sets up a RANK environment variable for each process.
              # This can be used to detect the master process.
              # See https://github.com/pytorch/pytorch/blob/master/torch/distributed/launch.py#L211
              # Except for errors, only the master process will send notifications.
              if "RANK" in os.environ:
                  master_process = int(os.environ["RANK"]) == 0
                  host_name += " - RANK: %s" % os.environ["RANK"]
              else:
                  master_process = True
  
              if master_process:
                  contents = [
                      "Your training has started 🎬",
                      "Machine name: %s" % host_name,
                      "Main call: %s" % func_name,
                      "Starting date: %s"
                      % start_time.strftime(DATE_FORMAT),
                      " ".join(user_mentions),
                  ]
                  dump["Content"] = "\n".join(contents)
                  requests.post(url=webhook_url, json=dump)
  
              try:
                  value = func(*args, **kwargs)
  
                  if master_process:
                      end_time = datetime.datetime.now()
                      elapsed_time = end_time - start_time
                      contents = [
                          "Your training is complete 🎉",
                          "Machine name: %s" % host_name,
                          "Main call: %s" % func_name,
                          "Starting date: %s"
                          % start_time.strftime(DATE_FORMAT),
                          "End date: %s"
                          % end_time.strftime(DATE_FORMAT),
                          "Training duration: %s" % str(elapsed_time),
                      ]
  
                      try:
                          str_value = str(value)
                          contents.append(
                              "Main call returned value: %s" % str_value
                          )
                      except:
                          contents.append(
                              "Main call returned value: %s"
                              % "ERROR - Couldn't str the returned value."
                          )
  
                      contents.append(" ".join(user_mentions))
                      dump["Content"] = "\n".join(contents)
                      requests.post(url=webhook_url, json=dump)
  
                  return value
  
              except Exception as ex:
                  end_time = datetime.datetime.now()
                  elapsed_time = end_time - start_time
                  contents = [
                      "Your training has crashed ☠️",
                      "Machine name: %s" % host_name,
                      "Main call: %s" % func_name,
                      "Starting date: %s"
                      % start_time.strftime(DATE_FORMAT),
                      "Crash date: %s" % end_time.strftime(DATE_FORMAT),
                      "Crashed training duration: %s\n\n"
                      % str(elapsed_time),
                      "Here's the error:",
                      "%s\n\n" % ex,
                      "Traceback:",
                      "%s" % traceback.format_exc(),
                      " ".join(user_mentions),
                  ]
                  dump["Content"] = "\n".join(contents)
                  requests.post(url=webhook_url, json=dump)
                  raise ex
  
          return wrapper_sender
  
      return decorator_sender
  
file_path: knockknock/knockknock/chime_sender.py
imports: import datetime
  import functools
  import os
  import socket
  import traceback
  from typing import List
  import requests
label_desc: Use image node_id 1 for calling a global function with example usage: chime_sender(webhook_url, user_mentions) and returns: decorator_sender, wrapper_sender, value