code: public void addOneToManyValue(String name, AssociationValue value) {
  		Attribute attribute = getAttributes().get(name);
  		if (!(attribute instanceof OneToManyAttribute)) {
  			throw new IllegalStateException("Cannot set oneToMany value on attribute with different type, " +
  					attribute.getClass().getName() + " setting value " + value);
  		}
  		OneToManyAttribute oneToMany = (OneToManyAttribute) attribute;
  		if (oneToMany.getValue() == null) {
  			oneToMany.setValue(new ArrayList<AssociationValue>());
  		}
  		oneToMany.getValue().add(value);
  	}
docs: Set attribute value of given type.
  
  @param name attribute name
  @param value attribute value