old_contents: # encoding: utf-8
  
  """
  .. codeauthor:: Tsuyoshi Hombashi <gogogo.vm@gmail.com>
  """
  
  from __future__ import absolute_import
  
  
  class EmptyPingStaticticsError(Exception):
      """
      Raised when a ping statistics is empty in a parsing text.
      """
  
new_contents: # encoding: utf-8
  
  """
  .. codeauthor:: Tsuyoshi Hombashi <gogogo.vm@gmail.com>
  """
  
  from __future__ import absolute_import
  
  
  class PingStaticticsHeaderNotFoundError(Exception):
      """
      Raised when a ping statistics header is not found in a parsing text.
      """
  
  
  class EmptyPingStaticticsError(Exception):
      """
      Raised when a ping statistics is empty in a parsing text.
      """
  
subject: Add PingStaticticsHeaderNotFoundError class