'Return data about VM diagnostics.'

def _get_diagnostics(self, instance):

    vm_ref = vm_util.get_vm_ref(self._session, instance)
    lst_properties = ['summary.config', 'summary.quickStats', 'summary.runtime']
    vm_props = self._session._call_method(vutil, 'get_object_properties_dict', vm_ref, lst_properties)
    data = {}
    for value in vm_props.values():
        prop_dict = vim_util.object_to_dict(value, list_depth=1)
        data.update(prop_dict)
    return data
