Can not call inherited method on nested class, when another nested class inherits from it and defines an override. #1787

namespace pythonnet_testing {
  public class Creator {
    public static object CreateObject() =>
      new BaseClass.NestedClass();
  }

  public class BaseClass {


    public virtual string GetSignal() =>
      "hello";

    public class NestedClass : BaseClass {
      // NOTE: This is using the default `GetSignal` implementation
    }

    // NOTE: This class inherits from the nested class, and overrides the method in the base class
    // When this class is defined, we can no longer call `GetSignal` on instances of `NestedClass`
    // ==> `Unhandled exception. Python.Runtime.PythonException: 'NestedClass' object has no attribute 'GetSignal'`
    public class InheritFromNested : BaseClass.NestedClass {
      public override string GetSignal() =>
        "override";
    }
  }


  class Program {
    static void Main(string[] args) {
      var pyCode = @"
import pythonnet_testing
o = pythonnet_testing.Creator.CreateObject()
print(f'Method call: {o.GetSignal()}')
      ";
      Runtime.PythonDLL = "libpython3.9.dylib";
      PythonEngine.Initialize();

      using (Py.GIL()) {
        PythonEngine.Exec(pyCode);
      }

      PythonEngine.Shutdown();
    }
  }
}