def cross(A, B):
    """Calculate cross product of two vectors.

    Parameters
    ----------
    A, B : list of float
        Vectors to be multiplied.

    Returns
    -------
    float
        Cross product of `A` and `B`.
    """
    return [
        A[1] * B[2] - A[2] * B[1],
        A[2] * B[0] - A[0] * B[2],
        A[0] * B[1] - A[1] * B[0],
        ]