text: import atexit, json
  from datetime import datetime
  from threading import Thread
  from urllib.request import Request, urlopen
  
  
  _format = '%Y-%m-%d %H:%M:%S.%f'
  _file = None
  _run_name = None
  _slack_url = None
  
  
  def init(filename, run_name, slack_url=None):
    global _file, _run_name, _slack_url
    _close_logfile()
    _file = open(filename, 'a', encoding="utf-8")
    _file.write('\n-----------------------------------------------------------------\n')
    _file.write('Starting new training run\n')
    _file.write('-----------------------------------------------------------------\n')
    _run_name = run_name
    _slack_url = slack_url
  
  
  def log(msg, slack=False):
    print(msg)
    if _file is not None:
      _file.write('[%s]  %s\n' % (datetime.now().strftime(_format)[:-3], msg))
    if slack and _slack_url is not None:
      Thread(target=_send_slack, args=(msg,)).start()
  
  
  def _close_logfile():
    global _file
    if _file is not None:
      _file.close()
      _file = None
  
  
  def _send_slack(msg):
    req = Request(_slack_url)
    req.add_header('Content-Type', 'application/json')
    urlopen(req, json.dumps({
      'username': 'tacotron',
      'icon_emoji': ':taco:',
      'text': '*%s*: %s' % (_run_name, msg)
    }).encode())
  
  
  atexit.register(_close_logfile)
  