from typing import List


def get_one_positions_in_binary_mask(mask: List[int]) -> List[int]:
    """
    Return the indices of one positions in a binary mask.

    :param mask: a mask that contains either 0s or 1s
    :return: List of indices of positions of ones in a binary mask.
    """

    mask_one_positions = [idx for (idx, channel) in enumerate(mask) if channel]
    return mask_one_positions