def filter_data_points(x, y, xmin, xmax, ymin, ymax):
    """
    Remove points outside the axes limits
    """
    xnew, ynew = [], []
    for xi, yi in zip(x, y):
        if xi is None or yi is None:
            continue
        elif xmin <= xi <= xmax and ymin <= yi <= ymax:
            xnew.append(xi)
            ynew.append(yi)
    return xnew, ynew