Does not support walrus-operator (Python 3.8)

[velle]

E.g.:

if (n := len(a)) > 10:
    print(f"List is too long ({n} elements, expected <= 10)")

Gives:

Error, got an unexpected token COLON here:

  1 if (n :<---- here

The token COLON should be one of those: COMMA, FOR, RIGHT_PARENTHESIS

More info on the walrus operator here: https://docs.python.org/3/whatsnew/3.8.html