This inspection reports the overridden methods (the methods with the same selector in the overridden classes) that have different parameter or
return types comparing to the base method's types. The return type is covariant, i.e. an overridden method can return any subtype of the base method's return type.
Parameter types are contravariant, i.e. an overridden method can have parameters of any superclass of the base method's parameter types. Covariance and
contravariance are applicable only to object types.