fix to new functioning

germany_dinn_sir.ipynb

@@ -420,7 +420,7 @@
     "    dataset = PandemicDataset(dataset_name, ['S', 'I', 'R'], 83100000, *covid_data)\n",
     "    problem = SIRProblem(dataset)\n",
     "    dinn = DINN(3, dataset, ['alpha', 'beta'], problem, plotter)\n",
-    "    dinn.configure_training(1e-3, 10000, scheduler_name='PolynomialLR', verbose=True)\n",
+    "    dinn.configure_training(1e-3, 10000, scheduler_name=Scheduler.POLYNOMIAL, verbose=True)\n",
     "    dinn.train(create_animation=True, animation_sample_rate=100, verbose=True)\n",
     "    dinn.plot_training_graphs()"
    ]