new_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  """Task 02"""
  
  
  class CustomError(Exception):
      """A custom exception class.
      Attributes:
          Exception(class): an exception class.
              cause(str): a string parameter.
      Args:
          Exception: an exception class.
      """
      def __init__(self, message, cause):
          """A constructor.
          Args:
              message(str): a string parameter.
              cause(str): a string parameter.
          Returns:
              Returns a custom class exception.
          Examples:
          >>> myerr = CustomError('Whoah!', cause='Messed up!')
          >>> print myerr.cause
          Messed up!
          """
          Exception.__init__(self)
          self.message = message
          self.cause = cause
  
subject: Create task_02.py