docs: @SuppressWarnings("static-method")
  	protected boolean isUnpureOperationPrototype(XtendFunction operation) {
  		if (operation == null
  				|| operation.isAbstract() || operation.isDispatch() || operation.isNative()
  				|| operation.getExpression() == null) {
  			return true;
  		}
  		final XtendTypeDeclaration declaringType = operation.getDeclaringType();
  		return declaringType instanceof SarlCapacity;
  	}