الدوال (Functions)

def add_vat(price, rate=0.14):      # rate has a default value
    """Return the price after adding VAT."""
    return price * (1 + rate)

print(add_vat(100))                   # uses default 14%
print(add_vat(100, 0.05))             # custom rate
print(add_vat(rate=0.10, price=500))  # keyword arguments

# NOTE: simplified prices for learning, not real tariffs
def electricity_bill(kwh):
    if kwh <= 50:
        return kwh * 0.68
    elif kwh <= 100:
        return 50 * 0.68 + (kwh - 50) * 0.78
    else:
        return 50 * 0.68 + 50 * 0.78 + (kwh - 100) * 0.95

for usage in [40, 90, 250]:
    print(f"{usage} kWh -> {electricity_bill(usage):.2f} EGP")