old_contents: class DoesNotExist(Exception):
      "The query returned no results when exactly one was expected."
      silent_variable_failure = True
  
  class ReturnedMultiple(Exception):
      "The query returned multiple results when only one was expected."
      pass
  
new_contents: from eulcore.existdb.db import ExistDBException
  
  class DoesNotExist(ExistDBException):
      "The query returned no results when exactly one was expected."
      silent_variable_failure = True
  
  class ReturnedMultiple(ExistDBException):
      "The query returned multiple results when only one was expected."
      pass
  
subject: make existdb custom exceptions inherit from existdbexception