catching blocks and getting the geometry

here is some code for getting some blockdefinition into grasshopper an parse it as geometry:

  private void RunScript(Guid guid_in, ref object A)
  {

    Rhino.Geometry.GeometryBase geo_base;
    List<object> geo_base_list = new List<object>();
    Rhino.DocObjects.InstanceDefinition instdef;
    Rhino.DocObjects.RhinoObject temp_obj_rh = doc.Objects.Find(guid_in);
    Rhino.DocObjects.InstanceObject temp_ins_rh;

    if( temp_obj_rh.ObjectType == Rhino.DocObjects.ObjectType.InstanceReference)
    {
      temp_ins_rh = temp_obj_rh as  Rhino.DocObjects.InstanceObject;
      instdef = temp_ins_rh.InstanceDefinition;
      geo_base = instdef.GetObjects()[0].Geometry;
      geo_base.Transform(temp_ins_rh.InstanceXform);
    }
    else
    {
      geo_base = temp_obj_rh.Geometry;
    }

    A = geo_base;

  }