Сергей Горностаев

from os.path import splitext

class ItemChat(models.Model):
    ...

    design_img = models.ImageField(blank=True, null=True,
        upload_to=lambda obj, name: str(obj.item.client) + splitext(name)[1])

MOV     DX, 2000         ; Number of times to repeat whole routine.

MOV     BX, 1            ; Frequency value.

MOV     AL, 10110110B    ; The Magic Number (use this binary number only)
OUT     43H, AL          ; Send it to the initializing port 43H Timer 2.

NEXT_FREQUENCY:          ; This is were we will jump back to 2000 times.

MOV     AX, BX           ; Move our Frequency value into AX.

OUT     42H, AL          ; Send LSB to port 42H.
MOV     AL, AH           ; Move MSB into AL  
OUT     42H, AL          ; Send MSB to port 42H.

IN      AL, 61H          ; Get current value of port 61H.
OR      AL, 00000011B    ; OR AL to this value, forcing first two bits high.
OUT     61H, AL          ; Copy it to port 61H of the PPI Chip
                         ; to turn ON the speaker.

MOV     CX, 100          ; Repeat loop 100 times
DELAY_LOOP:              ; Here is where we loop back too.
LOOP    DELAY_LOOP       ; Jump repeatedly to DELAY_LOOP until CX = 0


INC     BX               ; Incrementing the value of BX lowers 
                         ; the frequency each time we repeat the
                         ; whole routine

DEC     DX               ; Decrement repeat routine count

CMP     DX, 0            ; Is DX (repeat count) = to 0
JNZ     NEXT_FREQUENCY   ; If not jump to NEXT_FREQUENCY
                         ; and do whole routine again.

                         ; Else DX = 0 time to turn speaker OFF

IN      AL, 61H          ; Get current value of port 61H.
AND     AL, 11111100B    ; AND AL to this value, forcing first two bits low.
OUT     61H, AL          ; Copy it to port 61H of the PPI Chip
                         ; to turn OFF the speaker.

class SomeFormHandler(FormView):
    def form_invalid(self, form):
        if self.request.is_ajax():
            data = {'status': 'error', 'erros': []}
            for field, errors in form.errors.items():
                for error in errors:
                    data['errors'].append({'key': field, 'desc': error})
            return JsonResponse(data)
        else:
            ...

$.post($(form).attr('action'), $(form).serialize(), function(result) {
    if(result.status == 'ok') {
        form.reset();
        showAlert('Сообщение успешно отправлено', 'success');
    }
    else if(result.status == 'error') {
        for(var ndx in result.errors) {
            if(result.errors[ndx].key == '__all__') showAlert(result.errors[ndx].desc);
            $(form).find('[name=' + result.errors[ndx].key + ']').parent().addClass('has-error');
        }
    }
}).fail(function(xhr, textStatus, error) {
    showAlert('Ошибка отправки сообщения');
});

for item in some_qs.all():
    ...

for item in some_qs.iterator():
    ...

import asyncio

from aiogram import Bot, types
from aiogram.dispatcher import Dispatcher
from aiogram.utils import executor

DELAY = 7200

bot = Bot(token='BOT TOKEN HERE')
dp = Dispatcher(bot)

@dp.message_handler(commands=['start', 'help'])
async def send_welcome(message: types.Message):
    await message.reply("Hi!\nI'm EchoBot!\nPowered by aiogram.")


async def update_price():
    ...


def repeat(coro, loop):
    asyncio.ensure_future(coro(), loop=loop)
    loop.call_later(DELAY, repeat, coro, loop)


if __name__ == '__main__':
    loop = asyncio.get_event_loop()
    loop.call_later(DELAY, repeat, update_price, loop)
    executor.start_polling(dp, loop=loop)

def __str__(self):
    return '{}, ({})'.format(self.title, self.products.count())

1. В обязанности fullstack-разработчика на чём угодно входит всё. Иначе он не fullstack.
   
2. Могу посоветовать взять учебник по Node.js (например) и официальную документацию AWS.