How to generate mesh on selected body with and without looping?

While looping one can use the following code :

currentIds = ExtAPI.SelectionManager.CurrentSelection.Ids
for id in currentIds :
  geoBody = ExtAPI.DataModel.GeoData.GeoEntityById(id)
  treeBody = ExtAPI.DataModel.Project.Model.Geometry.GetBody(geoBody)
  treeBody.GenerateMesh()

and without looping (after activating all tree objects) :

cmd="""DS.Script.doModelPreviewMesh();"""
ds=ExtAPI.Application.ScriptByName("jscript").ExecuteCommand(cmd)