Where can I find the complete AutoCAD & Civil 3D API for Python resources?

I have a piece of code as shown in the figure. I want to change Polyline3d to 2dPline on line 462. I have tried Polyline_2d, Polyline2d, Polyline … etc. It didn’t work.
After GOOGLE, I got this:

public void AddAllowedClass(
    Type type, 
    [MarshalAs(UnmanagedType.U1)] bool exactMatch

Which keyword of Type should I use?

Actually, I want to know more about AutoCAD & Civil 3D API for Python.
Any help would be greatly appreciated!