Implementation.cs

//abstract class the acts as the functionality implementation
public abstract class BaseImplementation : TypesData.ImplementationBase
{
    void Start()
    {
        Method();
    }

    protected virtual void Method()
    {
        Debug.Log("Implementation Method");
    }
}

//empty partial class that derives the implementation, should be used as if implementation
public partial class Implementation : BaseImplementation
{

}