Update app.py

app.py

@@ -24,13 +24,26 @@ def plot_usage_volume(system1, users1, timeline1, system2, users2, timeline2):
 
     # Create a multiline plot of the usage volume for each system
     line = alt.Chart(data).mark_line().encode(
-        x='Month:N',
+        x=alt.X('Month', sort=list(data['Month'].unique())),
         y='Usage:Q',
         color='System:N'
     ).properties(title="System Rollout Usage Volume Plot")
 
+    # Create an aggregated line for the total usage across both systems
+    aggregated_data = data.groupby(['Month']).sum().reset_index()
+    aggregated_data['System'] = 'Total'
+    data = pd.concat([data, aggregated_data], axis=0)
+
+    aggregated_line = alt.Chart(aggregated_data).mark_line(color='black').encode(
+        x=alt.X('Month', sort=list(data['Month'].unique())),
+        y='Usage:Q'
+    )
+
+    # Combine the multiline and aggregated line plots
+    chart = alt.layer(line, aggregated_line)
+
     # Return the plot as a Gradio output
-    return line
+    return chart
 
 # Define the input components
 inputs = [