def _valid_hull(geoms, points):
    """
    Sanity check within ``alpha_shape_auto()`` to verify the generated
    alpha shape actually contains the original set of points (xys).
    
    Parameters
    ----------
    
    geoms   : GeoSeries
              see alpha_geoms()
    points  : list
              xys parameter cast as shapely.geometry.Point objects
    
    Returns
    -------
    
    flag    : bool
              Valid hull for alpha shape [True] or not [False]
    
    """
    flag = True
    if geoms.shape[0] != 1:
        flag = False
    for point in points:
        if not point.intersects(geoms[0]):
            flag = False
    return flag
