Question: 
Write a function to find the top or bottom surface area of a cylinder.


Model's Code:
def topbottom_surfacearea(radius):
    import math
    return 2 * math.pi * radius ** 2



Sample Correct Code:
def topbottom_surfacearea(r):
  toporbottomarea=3.1415*r*r
  return toporbottomarea


Asserts:
assert topbottom_surfacearea(10)==314.15000000000003
assert topbottom_surfacearea(5)==78.53750000000001
assert topbottom_surfacearea(4)==50.264


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

Test 535 of 974: 394/535 (73.64485981308411%): failed