Calculate the Internal Rate of Return

def npv(rate, cash_flows):
    total = 0
    for t, cf in enumerate(cash_flows):
        total += cf / ((1 + rate) ** t)
    return total

def irr(cash_flows, guess=0.1, tol=1e-6, max_iter=1000):
    rate = guess
    for i in range(max_iter):
        # Calculate NPV and derivative (for Newton-Raphson)
        npv_val = 0
        d_npv = 0
        for t, cf in enumerate(cash_flows):
            npv_val += cf / ((1 + rate) ** t)
            if t > 0:
                d_npv -= t * cf / ((1 + rate) ** (t + 1))
        
        # Update rate
        new_rate = rate - npv_val / d_npv
        
        if abs(new_rate - rate) < tol:
            return new_rate
        rate = new_rate
    return None

# Example usage
C0 = float(input("Enter initial investment \n(C0): "))
T = int(input("Enter number of periods \n(T): "))

cash_flows = [-C0]
for t in range(1, T + 1):
    Ct = float(input("Enter cash inflow for period {}: ".format(t)))
    cash_flows.append(Ct)

result = irr(cash_flows)
if result is not None:
    print("IRR: {:.2f}%".format(result * 100))
else:
    print("IRR calculation did not converge.")