quick fix

app.py

@@ -41,6 +41,7 @@ def cohort_predict(start_date, cohort_start, product):
     hist_seq = get_sequence(data, cohort_start, product)
 
     fig = plot_example_from_case(hist_seq, new_seq, 25, product)
+    fig.canvas.draw()
 
     arr = np.frombuffer(fig.canvas.tostring_rgb(), dtype=np.uint8)
     arr = arr.reshape(fig.canvas.get_width_height()[::-1] + (3,))