old_contents: # -*- coding: utf-8 -*-
  
  import unicodedata
  
  def remove_diacritic(input):
      '''
      Accept a unicode string, and return a normal string (bytes in Python 3)
      without any diacritical marks.
      '''
      return unicodedata.normalize('NFKD', input).encode('ASCII', 'ignore')
  
new_contents: # -*- coding: utf-8 -*-
  
  import unicodedata
  
  def remove_diacritic(input):
      '''
      Accept a unicode string, and return a normal string (bytes in Python 3)
      without any diacritical marks.
      '''
      return unicodedata.normalize('NFKD', input).encode('ASCII', 'ignore')
  
  
  class Singleton(type):
      """ Singleton metaclass. """
  
      def __init__(cls, name, bases, dct):
          cls.__instance = None
          type.__init__(cls, name, bases, dct)
   
      def __call__(cls, *args, **kw):
          if cls.__instance is None:
              cls.__instance = type.__call__(cls, *args,**kw)
          return cls.__instance
  
subject: Add singleton class.