Tab before operator (E223)

There should be only one space before or after operators.

Anti-pattern

Note: The → character represents a tab.

if x→in [1, 2, 3]:
    print(x)

Best practice

if x in [1, 2, 3]:
    print(x)

Additional links

• https://www.python.org/dev/peps/pep-0008/#pet-peeves