Question: 
Write a function to caluclate arc length of an angle.


Model's Code:
def arc_length(radius, angle):
    if angle < 0 or angle >= 360:
        return None
    return 2 * 3.141592653589793 * radius * (angle / 360)



Sample Correct Code:
def arc_length(d,a):
    pi=22/7
    if a >= 360:
        return None
    arclength = (pi*d) * (a/360)
    return arclength


Asserts:
assert arc_length(9,45)==3.5357142857142856
assert arc_length(9,480)==None
assert arc_length(5,270)==11.785714285714285


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

Test 761 of 974: 575/761 (75.55847568988173%): failed