Chess960 Initial Position Generator (Python)

chess960.py

#!/usr/bin/env python
import random

def empty(lst):
    return [i for i, value in enumerate(lst) if value == 0]

board = [0] * 8

# Bishops
for i in range(2):
    r = random.randrange(0, 7, 2) + i
    board[r] = 'B'

# Queen, Knights
for i, piece in zip(random.sample(empty(board), 3), list('QNN')):
    board[i] = piece

# Rook, King, Rook
for i, piece in zip(empty(board), list('RKR')):
    board[i] = piece

# Print board
print(' '.join(map(str, board)))