EP 14 Prefer Exceptions to Returning `None` ref: http://qiita.com/giwa/items/5ba9386970bcbccd0b80

file0.txt

def divide(a, b):
    try:
        return a/b
    except ZeroDivisionError:
        return None

file1.txt

result = divide(x, y)
if result is None:
  print('Invalid inputs')

file2.txt

x, y = 0, 5
result = divide(x, y)
if not result:
  print('Invalid inputs')

file3.txt

def divide(a, b):
    try:
        return True, a/b
    except ZeroDivisionError:
        return False, None

file4.txt

def divide(a, b):
    try:
        return a/b
    except ZeroDivisionError as e:
        raise ValueError('Invalid inputs') from e