def _string_difference_indices(s1, s2):
    """
    Returns all indices where s1 and s2 differ.

    Args:
        s1: The first sequence.
        s2: The second sequence.

    Returns:
        List of indices where s1 and s2 differ.
    """
    return [index for index in range(len(s1)) if s1[index] != s2[index]]