old_contents: # encoding: utf-8
  
  import sys
  
  
  class _const(object):
      class ConstError(TypeError):
          pass
  
      class ConstCaseError(ConstError):
          pass
  
      def __setattr__(self, name, value):
          if name in self.__dict__:
              raise self.ConstError, "Can't change const.{0}".format(name)
  
          if not name.isupper():
              raise self.ConstCaseError, 'const name "{0}" is not all uppercase'.format(name)
  
          self.__dict__[name] = value
  
  
  sys.modules[__name__.title()] = _const
  sys.modules[__name__] = _const()
  
new_contents: # encoding: utf-8
  
  import sys
  
  
  class _const(object):
      class ConstError(TypeError):
          pass
  
      class ConstCaseError(ConstError):
          pass
  
      def __setattr__(self, name, value):
          if name in self.__dict__:
              raise self.ConstError("Can't change const.{0}".format(name))
  
          if not name.isupper():
              raise self.ConstCaseError('const name "{0}" is not all uppercase'.format(name))
  
          self.__dict__[name] = value
  
  
  sys.modules[__name__.title()] = _const
  sys.modules[__name__] = _const()
  
subject: Fix a bug on Python 3.6