Simplify grabbing single signal history

damper/system.py

@@ -65,7 +65,7 @@ def run_experiment():
 
     time_values = []
     y_values = []
-    for signal in smd.getSignals()["y"]:
+    for signal in smd.getSignalHistory("y"):
         time_values.append(signal.time)
         y_values.append(signal.value)
     fig, ax = plt.subplots(figsize=(5, 5), dpi=100)