You’ll need to wait until the next V7 WIP (probably available on Feb 25, 2020). At that point you should be able to use a script like the following.
private void RunScript(string path, ref object A)
{
using( var doc = Rhino.RhinoDoc.CreateHeadless(null) )
{
doc.Import(path);
var geometry = new System.Collections.Generic.List<GeometryBase>();
foreach(var obj in doc.Objects)
{
geometry.Add(obj.Geometry.Duplicate());
}
A = geometry;
}
}