ग्रैन्युलर CLV की गणना करें

# Calculate average revenue per invoice
revenue_per_purchase = online.___(['___'])['TotalSum'].mean().mean()

# Calculate average number of unique invoices per customer per month
frequency_per_month = online.___(['CustomerID','InvoiceMonth'])['___'].___().mean()

# Define lifespan to 36 months
lifespan_months = 36

# Calculate granular CLV
clv_granular = ___ * frequency_per_month * lifespan_months

# Print granular CLV value
print('Average granular CLV is {:.1f} USD'.format(clv_granular))