Trying to develop a simple text editor. How to fix a addch error?

Question

import curses
import curses.ascii

class text:
     def __init__(self, win):
     ┊   self.win = win
     ┊   self.lastcmd = ''
     ┊   self.ch = self.win.getch()
     
     def cursor_curr_position(self):
     ┊   (c_line, c_row) = self.win.getyx()
     ┊   return c_line, c_row
    
     def validate(self, ch):
     ┊   if curses.ascii.isprint(ch):
     ┊   ┊   self.win.addch(ch)
 
     def editor(self):
     ┊   curses.cbreak()
     ┊   curses.raw()
     ┊   while True:
     ┊   ┊   self.win.addch(self.ch)
 
if __name__ == '__main__':
     def main(stdscr):
     ┊   win = curses.newwin(10, 10, 0, 0)
     ┊   
     ┊   return text(win).editor()
curses.wrapper(main)  

I'm try to write a simple terminal text editor. When I run this code a new terminal window show up. when I try to insert some char I get this error:

_curses.error: addch() returned ERR

Someone have an idea on how to fix?

Answer 1

import curses
import curses.ascii

class text:
     def __init__(self, win):
     ┊   self.win = win
     ┊   self.lastcmd = ''
     
     def cursor_curr_position(self):
     ┊   (c_line, c_row) = self.win.getyx()
     ┊   return c_line, c_row
    
     def validate(self, ch):
     ┊   if curses.ascii.isprint(ch):
     ┊   ┊   self.win.addch(ch)
 
     def editor(self):
     ┊   curses.cbreak()
     ┊   curses.raw()
     ┊   while True:
             ch = self.win.getch()
             self.validate(ch)
 
if __name__ == '__main__':
     def main(stdscr):
     ┊   win = curses.newwin(10, 10, 0, 0)
     ┊   
     ┊   return text(win).editor()
curses.wrapper(main)  

I've put getch() variable after the while loop. Everything work fine!