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/*
	* OCL Constraint: UniqueIdentifiableInstance
	* Every EClass that implements Identifiable interface has an identifier attribute. The value of this attribute must be unique for each instance.
	* 
 */
abstract class Identifiable { interface }
{
	attribute identifier : String[1];
	attribute name : String[?];
	attribute description : String[?];
	invariant UniqueIdentifiableInstance: self.oclType().allInstances()->forAll(id1, id2 |id1 <> id2 implies id1.identifier <> id2.identifier);
}

class SomeOtherEClass extends ParentClass,Identifiable;
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