不进入下一个周期

Question

问题是btn.onclicked(callback.next)不会进入下一个循环，也不会得出下一个循环的点。请帮忙，我是python的新手

import matplotlib.pyplot as plt
import mdfreader
from matplotlib.widgets import Button

btn_next = plt.axes([0.78, 0.93, 0.06, 0.045])
bnext = Button(btn_next, 'Next -->', color='0.55', hovercolor='0.95')

class Index(object):
    global_cycle = 0

    def next(self, event):
        self.global_cycle += 1

callback = Index()
# crossing on the 40 objects
for i in range(number_ohy_objects):
    wExistProb = mdf_inf._getChannelData3('fus.ObjData_Qm_TC.FusObj.i' + str(i) + '.wExistProb')
    dx_Ohl_Obj = mdf_inf._getChannelData3('fus.ObjData_Qm_TC.FusObj.i' + str(i) + '.dxv')
    dy_Ohl_Obj = mdf_inf._getChannelData3('fus.ObjData_Qm_TC.FusObj.i' + str(i) + '.dyv')
    # check the value bigger than 0.1 and add into a list
    if wExistProb[global_cycle] > 0.1:
        obj_index.append(i)
        obj_dy.append(dy_Ohl_Obj[global_cycle])
        obj_dx.append(dx_Ohl_Obj[global_cycle])

    # plot the points
    aux = plt.scatter(obj_dy[:], obj_dx[:], color='green')

    bnext.on_clicked(callback.next)
    aux = plt.scatter(obj_dy[global_cycle], obj_dx[global_cycle] color='green')

plt.show()