用UI做出来了一个计算器，按键也都设置好了，什么布局都弄好了，然后再文件夹里新建一个文件，引用UI，想弹出一个计算器来，但点击弹出来的计算器就会could not convert string to float这个错误
代码：# 系统包
import sys
from PyQt5 import QtCore, QtGui, QtWidgets

项目包

from Ui_MainWindow import Ui_MainWindow

class CMainWindow(QtWidgets.QMainWindow, Ui_MainWindow):
def init(self, parent = None):
super(CMainWindow, self).__init__(parent)
self.setupUi(self)
# 主窗体设置

self.setFixedSize(self.width(), self.height())
self.show()

def AddNumber(self, number):
    if number == ".":
        if self.txtDisplay.text().find(".") == -1:
            self.txtDisplay.setText(self.txtDisplay.text() + number)
    else:
        if self.txtDisplay.text().find(".") == -1:
            if float(self.txtDisplay.text()) == 0:
                self.txtDisplay.setText("")
            self.txtDisplay.setText(self.txtDisplay.text() + number)
            if float(self.txtDisplay.text()) == 0:
                self.txtDisplay.setText("0")
        else:
            self.txtDisplay.setText(self.txtDisplay.text() + number)

def Push00(self):
    self.AddNumber("00")

def Push0(self):
    self.AddNumber("0")

def Push1(self):
    self.AddNumber("1")

def Push2(self):
    self.AddNumber("2")

def Push3(self):
    self.AddNumber("3")

def Push4(self):
    self.AddNumber("4")

def Push5(self):
    self.AddNumber("5")

def Push6(self):
    self.AddNumber("6")

def Push7(self):
    self.AddNumber("7")

def Push8(self):
    self.AddNumber("8")

def Push9(self):
    self.AddNumber("9")

def PushDot(self):
    self.AddNumber(".")

def PushClr(self):
    self.txtDisplay.setText("0")

def PushAdd(self):
    pass

def PushSub(self):
    pass

def PushMul(self):
    pass

def PushDiv(self):
    pass

def PushEqr(self):
    pass

if name == '__main__':
app = QtWidgets.QApplication(sys.argv)
MainWindow = CMainWindow()
sys.exit(app.exec_())

浮点数无法转换的错误，代码的问题