def distance_squared(x1, y1, x2, y2):
    """
    
    Helper function to return the square of the distance between
    points (x1,y1) and (x2,y2).

    :Parameters:

    x1: float
        X coordinate of first point
    y1: float
        Y coordinate of first point
    x2: float
        X coordinate of second point
    y2: float
        Y coordinate of second point

    :Returns:
    
    distsq: float
        The square of the distance, (x1-x2)**2 + (y1-y2)**2
    
    """
    xdiff = float(x1) - float(x2)
    ydiff = float(y1) - float(y2)
    distsq = (xdiff * xdiff) + (ydiff * ydiff)
    return distsq