Error

@bot.on(events.CallbackQuery)
async def ask(event):
    user_id = event.sender.id
    data = event.data.decode('utf-8')
    if data == 'Add Session':
        user_data[user_id] = {'step': 'ask_phone'}
        await event.edit('Send Phone Number: ex(+201111111111)')

@bot.on(events.NewMessage)
async def handler(event):
    user_id = event.sender_id
    if user_id not in user_data or 'step' not in user_data[user_id]:
        return
    step = user_data[user_id]['step']
    if step == 'ask_phone':
        user_data[user_id]['phone'] = event.raw_text.strip()
        user_data[user_id]['step'] = 'ask_code'
        user_data[user_id]['client'] = TelegramClient(
            f"sessions/{user_data[user_id]['phone']}", api_id, api_hash
        )
        await event.reply('Send The Code You Have Received: ex(77777)')
        await user_data[user_id]['client'].connect()
        await user_data[user_id]['client'].send_code_request(user_data[user_id]['phone'])
    elif step == 'ask_code':
        user_data[user_id]['code'] = event.raw_text.strip()
        user_data[user_id]['step'] = 'ask_password'
        try:
            await user_data[user_id]['client'].sign_in(user_data[user_id]['phone'], user_data[user_id]['code'])
            await event.reply(f"Session For {user_data[user_id]['phone']} Created Successfully")
            del user_data[user_id]
        except SessionPasswordNeededError:
            await event.reply('Send The 2FA Code: ex(123456)')
        except Exception as e:
            await event.reply(f'Error Happened: {e}')
            del user_data[user_id]
    elif step == 'ask_password':
        password = event.raw_text.strip()
        try:
            await user_data[user_id]['client'].sign_in(password)
            await event.reply(f"Session For {user_data[user_id]['phone']} Created Successfully")
            del user_data[user_id]
        except Exception as e:
            await event.reply(f'Error Happened: {e}')
            del user_data[user_id]