  
  
  class NotAuthenticated(APIException):
      status_code = status.HTTP_401_UNAUTHORIZED
      default_detail = _("Authentication credentials were not provided.")
  
  
  class PermissionDenied(APIException):
      status_code = status.HTTP_403_FORBIDDEN
      default_detail = _("You do not have permission to perform this action.")
 
</s> remove     default_detail = _("You do not have permission to perform this action.")
 </s> add     default_detail = _('You do not have permission to perform this action.') </s> remove     default_detail = _("Incorrect authentication credentials.")
 </s> add     default_detail = _('Incorrect authentication credentials.') </s> remove     default_detail = _("Malformed request.")
 </s> add     default_detail = _('Malformed request.') </s> remove     default_detail = _("Not found.")
 </s> add     default_detail = _('Not found.') </s> remove     default_detail = _("Method \"{method}\" not allowed.")
 </s> add     default_detail = _('Method "{method}" not allowed.')
    default_detail = _('Authentication credentials were not provided.')
  
  
  class NotAuthenticated(APIException):
      status_code = status.HTTP_401_UNAUTHORIZED
    default_detail = _('Authentication credentials were not provided.')
  
  
  class PermissionDenied(APIException):
      status_code = status.HTTP_403_FORBIDDEN
      default_detail = _("You do not have permission to perform this action.")
keep keep keep keep replace keep keep keep keep keep
 prefer single quotes in source and double quotes in user visible strings; add some missing full stops to user visible strings 
rest_framework/exceptions.py