MagFieldConfig clusterdir_fa0a4f3d60c75b40193e742901f02f45 MagneticField clusterdir_bddf4f1d3e5f771f830217e7dd1ad5da dir_bddf4f1d3e5f771f830217e7dd1ad5da MagFieldConfig dir_31c0fb0f2265cff8ec047beaec9a9930 python