new_contents: # -*- coding: utf-8 -*-
  
  """
  Exceptions
  
  """
  
  __all__ = [
      'PycelleException',
  ]
  
  class PycelleException(Exception):
      """
      Base class for all `pycelle` exceptions.
  
      """
      def __init__(self, *args, **kwargs):
          if 'msg' in kwargs:
              # Override the message in the first argument.
              self.msg = kwargs['msg']
          elif args:
              self.msg = args[0]
          else:
              self.msg = ''
          self.args = args
          self.kwargs = kwargs
  
      def __str__(self):
          return self.msg
  
      def __repr__(self):
          return "{0}{1}".format(self.__class__.__name__, repr(self.args))
  
subject: Add base exception class.