#NEWLINE# def errback( self , fail = None ) : #NEWLINE# #INDENT# "\n        Run all error callbacks that have been added to this L{Deferred}.\n\n        Each callback will have its result passed as the first\n        argument to the next; this way, the callbacks act as a\n        'processing chain'. Also, if the error-callback returns a non-Failure\n        or doesn't raise an L{Exception}, processing will continue on the\n        *success*-callback chain.\n\n        If the argument that's passed to me is not a L{failure.Failure} instance,\n        it will be embedded in one. If no argument is passed, a\n        L{failure.Failure} instance will be created based on the current\n        traceback stack.\n\n        Passing a string as `fail' is deprecated, and will be punished with\n        a warning message.\n\n        An instance of L{Deferred} may only have either L{callback} or\n        L{errback} called on it, and only once.\n\n        @param fail: The L{Failure} object which will be passed to the first\n            errback added to this L{Deferred} (via L{addErrback}).\n            Alternatively, a L{Exception} instance from which a L{Failure} will\n            be constructed (with no traceback) or C{None} to create a L{Failure}\n            instance from the current exception state (with a traceback).\n\n        @raise AlreadyCalledError: If L{callback} or L{errback} has already been\n            called on this L{Deferred}.\n\n        @raise NoCurrentExceptionError: If C{fail} is C{None} but there is\n            no current exception state.\n        " #NEWLINE# if ( fail is None ) : #NEWLINE# #INDENT# fail = failure . Failure ( captureVars = self . debug ) #NEWLINE# #UNINDENT# else : #NEWLINE# #INDENT# if ( not isinstance ( fail , failure . Failure ) ) : #NEWLINE# #INDENT# fail = failure . Failure ( fail ) #NEWLINE# #UNINDENT# #UNINDENT# self . _startRunCallbacks ( fail )