I am an association holding only weakly on my key.

	comparing
	< = hash hashMappedBy: identityHashMappedBy:

	printing
	printOn: storeOn:

	accessing	top
	key Answer the lookup key of the receiver.
	key: Store the argument, anObject, as the lookup key of the receiver.
	key:value: Store the arguments as the variables of the receiver.

	comparing	top
	< Refer to the comment in Magnitude|<.
	= Compare the receiver with the argument and answer with true if the receiver is equal to the argument. Otherwise answer false.
	hash Hash is reimplemented because = is implemented.
	hashMappedBy: Answer what my hash would be if oops changed according to map.
	identityHashMappedBy: Answer what my hash would be if oops changed according to map.

	printing	top
	printOn: Append to the argument, aStream, a sequence of characters that identifies the receiver.
	storeOn: Store in the format (key->value)