docs: async def sign_in(self, event=None):
          """
          Note the `event` argument. This is required since this callback
          may be called from a ``widget.bind`` (such as ``'<Return>'``),
          which sends information about the event we don't care about.
  
          This callback logs out if authorized, signs in if a code was
          sent or a bot token is input, or sends the code otherwise.
          """
          self.sign_in_label.configure(text='Working...')
          self.sign_in_entry.configure(state=tkinter.DISABLED)
          if await self.cl.is_user_authorized():
              await self.cl.log_out()
              self.destroy()
              return
  
          value = self.sign_in_entry.get().strip()
          if self.code:
              self.set_signed_in(await self.cl.sign_in(code=value))
          elif ':' in value:
              self.set_signed_in(await self.cl.sign_in(bot_token=value))
          else:
              self.code = await self.cl.send_code_request(value)
              self.sign_in_label.configure(text='Code:')
              self.sign_in_entry.configure(state=tkinter.NORMAL)
              self.sign_in_entry.delete(0, tkinter.END)
              self.sign_in_entry.focus()
              return