'connect' widget classes in an application

In the code below I get the error below.
I'm trying to create a class for several widgets and make the "interact" 
within a main Frame. Can't figure it out (lack of programming 
experience) and couldn't find an eye opening example.

I understand that the toolbar has no way to access the txt in the 
editor, how do I make it so?

TIA,

Ingo

ERROR:

Exception in Tkinter callback
Traceback (most recent call last):
   File "\Python35-32\lib\tkinter\__init__.py", line 1549, in __call__
     return self.func(*args)
   File "twoclass.py", line 10, in <lambda>
     command=lambda: self.txt.insert(END, 'Button pressed.\n')
AttributeError: 'Ttoolbar' object has no attribute 'txt'


CODE:

from tkinter import *

class Ttoolbar(Frame):

     def __init__(self, parent=None):
         Frame.__init__(self, parent)
         self.btn = Button(
             self,
             text='Button',
             command=lambda: self.txt.insert(END, 'Button pressed.\n')
         )
         self.btn.pack(side=LEFT)
         self.pack(side=LEFT)


class Eedit(Text):

     def __init__(self, parent=None):
         txt = Text.__init__(self, parent)
         self.pack(fill='both', expand=Y)


class Aapp(Frame):

     def __init__(self, parent=None):
         Frame.__init__(self, parent)
         self.pack()
         self.makeWidgets()


     def makeWidgets(self):
         tb = Ttoolbar().pack(side=TOP, fill=X)
         ed = Eedit().pack()


if __name__ == '__main__':
     Aapp().mainloop()