Question: 
Write a function to calculate electricity bill.


Model's Code:
def cal_electbill(units):
    if units <= 100:
        return units * 3.25
    elif units <= 200:
        return 100 * 3.25 + (units - 100) * 4.00
    elif units <= 300:
        return 100 * 3.25 + 100 * 4.00 + (units - 200) * 4.50
    else:
        return 100 * 3.25 + 100 * 4.00 + 100 * 4.50 + (units - 300) * 5.00



Sample Correct Code:
def cal_electbill(units):
 if(units < 50):
    amount = units * 2.60
    surcharge = 25
 elif(units <= 100):
    amount = 130 + ((units - 50) * 3.25)
    surcharge = 35
 elif(units <= 200):
    amount = 130 + 162.50 + ((units - 100) * 5.26)
    surcharge = 45
 else:
    amount = 130 + 162.50 + 526 + ((units - 200) * 8.45)
    surcharge = 75
 total = amount + surcharge
 return total


Asserts:
assert cal_electbill(75)==246.25
assert cal_electbill(265)==1442.75
assert cal_electbill(100)==327.5


Tests:
Test 1 of 3: FAIL: AssertionError()

Test 136 of 974: 101/136 (74.26470588235294%): failed