Letter of Credit (LC) Usance Bill Discounting & Effective Yield Calculator in Python

def calculate_lc_bill_discounting(bill_amount, usance_days=90, grace_days=3, discount_rate_pa=9.25, commission_pct=0.15):
    total_days = usance_days + grace_days
    discount_interest = bill_amount * (discount_rate_pa / 100.0) * (total_days / 365.0)
    commission = bill_amount * (commission_pct / 100.0)
    net_proceeds = bill_amount - discount_interest - commission
    
    effective_yield_pa = ((discount_interest + commission) / net_proceeds) * (365.0 / total_days) * 100.0
    return {
        'Gross_Bill_Amount': round(bill_amount, 2),
        'Chargeable_Days': total_days,
        'Upfront_Discount_Interest': round(discount_interest, 2),
        'Bank_Commission': round(commission, 2),
        'Net_Payout_To_Seller': round(net_proceeds, 2),
        'Effective_Annual_Cost_Pct': round(effective_yield_pa, 2)
    }