Text character replacer with gui

main.py

import kivy
from kivy.app import App
from kivy.uix.label import Label
from kivy.uix.gridlayout import GridLayout
from kivy.uix.textinput import TextInput
from kivy.uix.button import Button
from kivy.config import Config

Config.set('input', 'mouse', 'mouse,multitouch_on_demand')

#GUI
class MyGridLayout(GridLayout):
    def __init__(self, **kwargs):
        super(MyGridLayout, self).__init__(**kwargs)
        self.textinputs = GridLayout()
        self.textinputs.cols = 3
        self.cols = 1
        self.text_ = TextInput(text = "Text")
        self.textinputs.add_widget(self.text_)
        self.toremove = TextInput(text = "What to replace")
        self.textinputs.add_widget(self.toremove)
        self.replace = TextInput(text = "What to replace with")
        self.textinputs.add_widget(self.replace)
        self.add_widget(self.textinputs)
        self.output = TextInput(text = "Output")
        self.add_widget(self.output)
        self.confirm = Button(text = "Confirm", font_size = 40)
        self.confirm.bind(on_press=self.pressed)
        self.add_widget(self.confirm)
#On button press    
    def pressed(self, instance):
        outputtxt = self.output
        replacewith = self.replace
        txt = self.text_
        toreplace =  self.toremove
        outputtxt.text = txt.text.replace(toreplace.text, replacewith.text)
#
class Replacer(App):
    def build(self):
        self.icon = "icon.png"
        return MyGridLayout()

#
if __name__ == "__main__":
    Replacer().run()