Is there a reason there is not an Interface for IntuitEntity?

Trying to make a generic repository pattern in our interface to the QBO api using the .NET SDK. It would be a lot easier if the classes that all inherit from IntuitEntity would also implement an IIntuitEntity interface so we could build generic methods for CRUD operations.

Or if the classes were labeled as Partial so we could extend them.

Or am I missing something that would allow this?