def colorbar_ticks_formatter(plot_object):
    fig, ax = plot_object.fig, plot_object.ax
    cax = fig.axes[1]
    formatter = multiples_of_pi()
    cax.yaxis.set_major_locator(formatter.MB_major_locator())
    cax.yaxis.set_major_formatter(formatter.MB_func_formatter())
#
u = symbols("u")
graphics(
    line_parametric_2d(
        2 * cos(u) + 5 * cos(2 * u / 3),
        2 * sin(u) - 5 * sin(2 * u / 3),
        (u, 0, 6 * pi)
    ),
    hooks=[colorbar_ticks_formatter]
)
# Expected:
## Plot object containing:
## [0]: parametric cartesian line: (5*cos(2*u/3) + 2*cos(u), -5*sin(2*u/3) + 2*sin(u)) for u over (0, 6*pi)