This abstract class is used as the parent of HealthPlan and HealthcarePolicy because there are many instances where one needs to refer to one or another. HealthPlan can be thought of as a generic product offering (e.g., Bronze, Silver, Gold plans), whereas the HealthcarePolicy is an individual instance of the Plan contracted to a given entity (either an individual or an organization such as an employer). However, some HealthPlans, such as a governmetn benefits plan do not have individual policies. Therefore, this superclass is used to generically reference either subclass as needed.