code: def convert_strtime_datetime(dt_str):
      
      dt, _, us = dt_str.partition(".")
      dt = datetime.datetime.strptime(dt, "%Y-%m-%dT%H:%M:%S")
      us = int(us.rstrip("Z"), 10)
      return dt + datetime.timedelta(microseconds=us)
docs: Converts datetime isoformat string to datetime (dt) object
  
      Args:
          :dt_str (str): input string in '2017-12-30T18:48:00.353Z' form
           or similar
      Returns:
          TYPE:  datetime object