import random


def roll_dice(num_dice):
    """Return a list of integers with length `num_dice`.

    Each integer in the returned list is a random number between
    1 and 6, inclusive.
    """
    roll_results = []
    for _ in range(num_dice):
        roll = random.randint(1, 6)
        roll_results.append(roll)
    return roll_results