Question: 
Write a function to find the volume of a cylinder.


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



Sample Correct Code:
def volume_cylinder(r,h):
  volume=3.1415*r*r*h
  return volume


Asserts:
assert volume_cylinder(10,5)==1570.7500000000002
assert volume_cylinder(4,5)==251.32000000000002
assert volume_cylinder(4,10)==502.64000000000004


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

Test 276 of 974: 198/276 (71.73913043478261%): failed