a1_1.py

import math
print(4.0 / 3.0 * math.pi * 5 * 5 * 5)

# Decimal points must be used for Python 2, where dividing two integers
# yields a truncated integer result, not the expected floating point value

def sphere_volume(r):
    return 4.0 / 3.0 * math.pi * r * r * r

print(sphere_volume(5))