import pandas as pd

sales = pd.DataFrame({
    "Customer ID": [101, 102, 103],
    "Order Total": [45.50, 72.00, 38.25],
    "Order Date": ["2026-06-01", "2026-06-02", "2026-06-03"],
})

rename_map = {
    "Customer ID": "customer_id",
    "Order Total": "order_total",
    "Order Date": "order_date",
}

renamed = sales.rename(columns=rename_map, errors="raise")

print(renamed)
print()
print("columns:", renamed.columns.tolist())
print("original:", sales.columns.tolist())
print("total:", renamed["order_total"].sum())