new_contents: #!/usr/bin/env python
  
  r"""
  This module contains functions having to do with date time filter.
  """
  
  from datetime import datetime
  
  
  def convert_string_dateime(date_str, date_format, desired_format):
      r"""
      Return a date time formatted from a string datetime.
  
      Description of arguments(s):
      date_str            Date time string e.g 2021072418161
                          or list ["2021072418161", "20210723163401"]
      date_format         Date time pattern of the string date time
                          e.g '%Y%m%d%H%M%S'
      desired_format      User define format e.g '%m/%d/%Y - %H:%M:%S'
      """
  
      if isinstance(date_str, list):
          tmp_date = []
          for date in date_str:
              tmp_date.append(datetime.strptime(date, date_format).strftime(desired_format))
          return tmp_date
      else:
          return datetime.strptime(date_str, date_format).strftime(desired_format)
  
subject: Add date time util module