code: def create_asset_model(self, ):
          
          rootdata = treemodel.ListItemData(['Name'])
          rootitem = treemodel.TreeItem(rootdata)
          prjs = djadapter.projects.all()
          for prj in prjs:
              prjdata = djitemdata.ProjectItemData(prj)
              prjitem = treemodel.TreeItem(prjdata, rootitem)
              for atype in prj.atype_set.all():
                  atypedata = djitemdata.AtypeItemData(atype)
                  atypeitem = treemodel.TreeItem(atypedata, prjitem)
                  for asset in atype.asset_set.filter(project=prj):
                      assetdata = djitemdata.AssetItemData(asset)
                      assetitem = treemodel.TreeItem(assetdata, atypeitem)
                      for typ in self.refobjinter.get_available_types_for_scene(asset):
                          typdata = treemodel.ListItemData([typ])
                          treemodel.TreeItem(typdata, assetitem)
  
          return treemodel.TreeModel(rootitem)
docs: Return a treemodel with the levels: project, assettype, asset and reftrack type
  
          :returns: a treemodel
          :rtype: :class:`jukeboxcore.gui.treemodel.TreeModel`
          :raises: None