old_contents: '''all custom exceptions should go here'''
  
  
  class InvalidDeckIssueModeCombo(Exception):
      '''When verfiying deck issue_mode combinations.'''
      pass
  
new_contents: '''all custom exceptions should go here'''
  
  
  class InvalidDeckIssueModeCombo(Exception):
      '''When verfiying deck issue_mode combinations.'''
  
  
  class UnsupportedNetwork(Exception):
      '''This network is not suppored by pypeerassets.'''
  
subject: add UnspupportedNetwork exception.