def find_point_of_region(vor, ireg):
    """Return the index of point within region ireg.

    Args:
        vor (Voronoi): Voronoi object.
        ireg (int): index of region.

    Returns:
        int: index of the Voronoi point for region ireg.

    """
    for ip, iregx in enumerate(vor.point_region):
        if iregx == ireg:
            return ip
    return None