def polygon_centroid(*points):
    """
    Calculates center point of given polygon.
    
    Args:
        points: ((float, float),)
            Collection of points as (x, y) coordinates.
    
    Returns:
        (float, float)
            Center point as (x, y) coordinates.
    """
    
    x = sum(p[0] for p in points) / len(points)
    y = sum(p[1] for p in points) / len(points)
    
    return x, y