proceeding from CLOS error

["\"Keith%GOJIRA.ATL.GE.COM\""%42.21.decnet@Warbucks.AI.SRI.COM]

(email replies to kmorgan@atl.ge.com)
 
Whenever I have to redefine a CLOS method with a new lambda pattern I
get a congruency error (see below), which means I have to type in new
defgeneric form for the sole purpose of getting my code to compile. Has
anyone hacked a proceed case to enable the lambda pattern to be
redefined?
 
1Error: The lambda list of the method #<STANDARD-READER-METHOD SCENELETS (SCENELET-COLLECTION) 31006723>,
0       1which is (SCENELET-COLLECTION), is not congruent
0       1with the lambda list of the generic function SCENELETS,
0       1which is (SCENELET-COLLECTION-TEMPORAL-PART &OPTIONAL .TIMESTAMP.), because
0       1the generic function has 1 optional argument but the method has 0 optional arguments.
 
#<STANDARD-METHOD ADD-METHOD (STANDARD-GENERIC-FUNCTION STANDARD-METHOD) 25570656>
0   Arg 0 (GENERIC-FUNCTION): #<STANDARD-GENERIC-FUNCTION SCENELETS 114244071>
   Arg 1 (CLOS-INTERNALS::.EXTRA-ARGUMENT.): #<Map for classes STANDARD-GENERIC-FUNCTION, STANDARD-READER-METHOD 25556744>
   Arg 2 (CLOS-INTERNALS::.GENERIC.): NIL
   Arg 3 (METHOD): #<STANDARD-READER-METHOD SCENELETS (SCENELET-COLLECTION) 31006723>
s-A, :    Skip compiling form (CLOS-INTERNALS::ENSURE-CLASS 'SCENELET-COLLECTION ...)
s-B:           Skip compiling form (DEFAULT-DEFCLASS SCENELET-COLLECTION ...)
s-C, :    Editor Top Level
s-D:           Restart process Zmacs Windows