def sub_vectors(a, b):
    """Subtracts two vectors.

    Args:
        pos1 (tuple[int]): first position
        pos1:(tuple[int]): second position

    Returns:
        tuple[int]: element wise subtraction

    Examples:
        >>> sub_vectors((1,4,6), (1,3,7))
        (0, 1, -1)
    """
    return tuple(a[i] - b[i] for i in range(3))