def check_angle(angle):
    """Check ``angle`` parameter and return as `int`.

    Parameters
    ----------
    angle : {0, 90, -90}

    Returns
    -------
    int

    Raises
    ------
    ValueError
    """
    if angle not in [0, 90, -90]:
        raise ValueError("'angle' must be 0, 90, or -90")

    return int(angle)