程序说显然是在使用tkinter时，未定义保存条目功能

Question

我一直在为学校项目构建一个注册程序，我的UI可以正常工作，但是由于某些原因，当我尝试使用next按钮保存输入时，该程序无法正常工作。 我尝试使用Lambda，而不使用Lambda：第二页显示了我开始使用的内容，第一页是我当前尝试的内容，但无济于事。 我不断收到错误

AttributeError: 'Reg1Page' object has no attribute 'SaveButton'

这是受影响功能的完整代码

class Reg1Page(tk.Frame):
def __init__(self,parent,controller):
    tk.Frame.__init__(self,parent)
    label = ttk.Label(self, text ='Registration Page', font =LargeFont)
    label.grid(row=0)

    label = ttk.Label(self,text = 'First Name').grid(row=1, column = 0, sticky ='n') 
    FirstName=ttk.Entry(self).grid(row=1, column = 1, sticky ='n')

    label = ttk.Label(self,text = 'Surname').grid(row=2, column = 0, sticky ='n') 
    Surname = ttk.Entry(self).grid(row=2, column = 1, sticky ='n')

    label = ttk.Label(self,text = 'Email').grid(row=3, column = 0, sticky ='n') 
    Email = ttk.Entry(self).grid(row=3, column = 1, sticky ='n')

    label = ttk.Label(self,text = 'Phone Number').grid(row=4, column = 0, sticky ='n')
    PhoneNum = ttk.Entry(self).grid(row=4, column = 1, sticky ='n')

    button1 = ttk.Button(self, text = 'Back to home', command= lambda: controller.showFrame(StartPage))
    button1.grid(row = 6, column = 0)

    button2 = ttk.Button(self, text = 'Next', command= lambda: self.SaveButton)
    button2.grid(row=6,column=1)

    def SaveButton(self):
        FNameS = self.FirstName.get()
        SNameS = self.Surname.get()
        EmailS = self.Email.get()
        PNumS = self.PhoneNum.get()
        controller.showFrame(Reg2Page)




class Reg2Page(tk.Frame):
def __init__(self,parent,controller):
    tk.Frame.__init__(self,parent)
    label = ttk.Label(self, text ='Reg Page', font =LargeFont).grid (row=0)

    label = ttk.Label(self,text = 'House Number').grid(row=1, column = 0, sticky ='n') 
    HNum=ttk.Entry(self).grid(row=1, column = 1, sticky ='n')

    label = ttk.Label(self,text = 'Street Name').grid(row=2, column = 0, sticky ='n') 
    SName = ttk.Entry(self).grid(row=2, column = 1, sticky ='n')

    label = ttk.Label(self,text = 'Postcode').grid(row=3, column = 0, sticky ='n') 
    PCode = ttk.Entry(self).grid(row=3, column = 1, sticky ='n')

    label = ttk.Label(self,text = 'PreviousPractice').grid(row=4, column = 0, sticky ='n')
    PPractice = ttk.Entry(self).grid(row=4, column = 1, sticky ='n')


    button1 = ttk.Button(self, text = 'Back to home', command= lambda: controller.showFrame(Reg1Page)).grid(row=6,column=0)


    button2 = ttk.Button(self, text = 'Confirm Registration', command= lambda: SaveButton()).grid(row=6,column=1)

    def SaveButton():
        HNumS = self.HNum.get()
        SNameS = self.SName.get()
        PCodeS = self.Pcode.get()
        PPracticeS = self.PPractice.get()
        popupMsg('Your registration has been successful')
        controller.showFrame(StartPage)`