Python Tkinter: Update entry field from another class - python-2.7

Question

I have a Python Tkinter GUI class as following:
import Tkinter as tk
class AppClient(tk.Frame):
def __init__(self, master):
error_class = ErrorClass()
self.val_error_code = error_class.error_message
tk.Frame.__init__(self, master)
self.pack()
##Frame for error message display
error_frame = tk.Frame(self, highlightbackground="violet", highlightcolor="violet", highlightthickness=1, width=600, height = 60, bd= 0)
error_frame.pack(padx = 10, pady = 5, anchor = 'w')
## error code: Label and Entry
tk.Label(error_frame, text = 'Error message').grid(row = 0, column = 0, sticky = 'w')
self.error_code = tk.Entry(error_frame, background = 'white', width = 27)
self.error_code.grid(row = 0, column = 1, sticky = 'w', padx = 5, pady = 5)
def update_error_messsage(self):
self.error_code.delete(0, 'end')
self.error_code.insert(0, self.val_error_code)
if __name__ == '__main__':
root = tk.Tk()
app_client = AppClient(root)
app_client.mainloop()
I want to update the entry field error_code dynamically by using the function update_error_message. The problem is, error message is continuously updated from another class ErrorClass() and I am receiving the error message to my AppClient class by variable error_message.
How can I update the error_code entry filed whenever the value of the variable error_message got updated in another class (ErrorClass())

Answer 1

The simple solution is that you need a reference to your instance of AppClient inside of ErrorClass, and then allow the instance of ErrorClass to pass the new value to the app
For example:
class AppClient(tk.Frame):
def __init__(self, master):
error_class = ErrorClass(self)
...
def update_error_messsage(self, error_code):
self.error_code.delete(0, 'end')
self.error_code.insert(0, error_code)
class ErrorClass():
def __init__(self, app):
self.app = app
def update_error(self):
...
error_code = 42
self.app.update_error_message(error_code)