PyQtGraph, рисование графика в реальном времени, за счёт изменения параметра

import pyqtgraph as pg
from PyQt5 import QtCore, QtGui, QtWidgets
import numpy as np
import graph
 
pg.setConfigOption('background', (240, 240, 240))
pg.setConfigOption('foreground', 'k')
 
pg.setConfigOptions(antialias=True)
 
 
class CustomPlot(pg.PlotWidget):
    def __init__(self):
        pg.PlotWidget.__init__(self)
        a = 1
        t = np.linspace(0, 2 * np.pi, num = 1000)
        self.x = a * np.sqrt(2) * np.cos(t) / (np.sin(t)**2 + 1)
        self.y = a * np.sqrt(2) * np.cos(t) * np.sin(t) / (np.sin(t)**2 + 1)
        self.plot(self.x, self.y, pen='k')
        self.showGrid(x=True, y=True)
 
 
class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
 
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(800, 400)
 
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
 
        self.verticalLayout = QtWidgets.QHBoxLayout(self.centralwidget)
        self.verticalLayout.setObjectName("verticalLayout")
 
 
        self.graphicsView = CustomPlot()
        self.verticalLayout.addWidget(self.graphicsView)
 
        self.checkBox = QtWidgets.QCheckBox(self.centralwidget)
        self.checkBox.setObjectName("checkBox")
        self.verticalLayout.addWidget(self.checkBox)
 
        self.spinBox = QtWidgets.QSpinBox(self.centralwidget)
        self.spinBox.setObjectName("spinBox")
        self.verticalLayout.addWidget(self.spinBox)
        
        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setObjectName("pushButton")
        self.verticalLayout.addWidget(self.pushButton)
 
        self.label = QtWidgets.QLabel(self.centralwidget)
        self.label.setObjectName("label")
        self.verticalLayout.addWidget(self.label)
 
        self.label_2 = QtWidgets.QLabel(self.centralwidget)
        self.label_2.setObjectName("label_2")
        self.verticalLayout.addWidget(self.label_2)
 
        MainWindow.setCentralWidget(self.centralwidget)
        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)
 
    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "График"))
        self.checkBox.setText(_translate("MainWindow", "Полярная система"))
        self.label.setText(_translate("MainWindow", "Formula1"))
        self.label_2.setText(_translate("MainWindow", "Formula2"))
        self.pushButton.setText(_translate("MainWindow", "Задать"))
 
 
if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())