close online window before showing final plot

Python_script/prototype.py

@@ -62,6 +62,7 @@ class Measurements:
         self.vna.create_new_trace("Trace4", "S22")
 
         self.measurement_plot = MeasurementPlot.MeasurementPlot()
+        self.data_collection = []
 
     def perform_measurements(self):
         with open(self.output, mode='w', newline='') as csv_file:
@@ -191,6 +192,8 @@ class Measurements:
 
                                 writer.writerow(measurement)
 
+                    plt.close()
+
                 except KeyboardInterrupt:
                     pass