How to add annotations (values) in pivot table using Python?

Question

Below is my data.

Sub-Region  sb1 sb2 sb3 sb4 sb5 sb6 sb7 sb8
Region                              
North       NaN NaN 2   NaN 9   1   NaN 2
South       3   4   NaN 7   NaN NaN 1   NaN

Below is my code.

v = v1.pivot_table(index='Region', columns='Sub-Region', values='Quantity')
v.plot.bar(stacked=True, figsize=(10,7))
plt.xticks(rotation=0)
plt.show()