from Tkinter import *
import tkSimpleDialog

class PersistentVariable:
        
    def __init__ (self, filename1):
       self.filename = filename1
       self.file = open(filename1,'a')
       self.file.close()
       print (self.file)

    def get (self):
       pass

    def modify (self, value):
       pass

    def modifyWithGui (self, value):
       pass

    def delete (self):
       pass

class PersistentString(PersistentVariable):

    def get (self):
       self.file = open(self.filename,'r')
       temp = self.file.readline()
       self.file.close()
       return temp

    def modify (self, value):
       self.file = open(self.filename,'w')
       self.file.write(value)
       self.file.close()

    def modifyWithGui (self):
       print(tkSimpleDialog.askstring("Persistent string.","Enter a string:" ))

    def delete (self):
       pass

root = Tk()
x = PersistentString("test")
x.modifyWithGui()