Both macros create a block of code in which simple variable names can be used to refer to slots on a 
particular object. At the minimum, a slot specifier names the slot, in which case the 
slot specifier can be just a name. On the other hand, 
:initargs needn't be exclusive--each :initarg option in a slot specifier creates a 
keyword parameter that can be used to initialize the slot; multiple parameters don't create a conflict, so 
the new slot specifier contains all the :initargs.
The &key in the parameter list is required to keep the method's parameter list 
congruent with the generic function's--the parameter list specified for 
the INITIALIZE-INSTANCE generic function includes &key in order to allow individual methods to supply their own keyword parameters but doesn't require any particular ones.
Java in which all the methods of a class must be defined as part of the class definition. 
Common Lisp also supports multiple inheritance--a class can have 
multiple direct superclasses, inheriting applicable methods and 
slot specifiers from all of them. Grâce à son gameplay innovant et ses fonctionnalités interactives, 
ce slot promet des parties aussi dynamiques qu’amusantes.

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