old_contents: from django.conf import settings
  
  class XmlJsonImportModuleException(Exception):
      pass
  
  
new_contents: from django.conf import settings
  
  class XmlJsonImportModuleException(Exception):
      pass
  
  if not hasattr(settings, 'XSLT_FILES_DIR'):
      raise XmlJsonImportModuleException('Settings must contain XSLT_FILES_DIR parameter')
  
subject: Throw exception for not existing XSLT_FILES_DIR setting