Сергей Горностаев

<div class="download">
    <form action="/Download/" method="post" enctype="multipart/form-data">
    {% csrf_token %}
    {{ form.as_p}}
        <div class="button_2">
        <button type="submit">Добавить</button>
        </div>
    </form>
</div>

def d(request):
    if request.method == 'POST':
        form = DownloadForm(request.POST, request.FILES)
        if form.is_valid():
            form.save()
            return HttpResponseRedirect('/main/')
        else:
            return render(request, 'downloader.html', {'form': form})
    else:
        form = DownloadForm()
        return render(request, 'downloader.html', {'form': form})

from django.contrib.admin.widgets import FilteredSelectMultiple

class TeamForm(forms.ModelForm):
    class Meta:
        model = Team
        fields = ('employees',)
        widgets = {
            'employees': FilteredSelectMultiple(u'Сотрудники', False),
        }
    class Media:
        css = {
            'all': ['admin/css/widgets.css'],
        }
        js = ['/admin/jsi18n/']

import sys
import time
from PyQt5 import QtCore, QtWidgets

class SlowTask(QtCore.QThread):
    updated = QtCore.pyqtSignal(int)
    running = False

    def __init__(self, *args, **kwargs):
        super(SlowTask, self).__init__(*args, **kwargs)
        self.percent = 0
        self.running = True

    def run(self):
        while self.running:
            self.percent += 1
            self.percent %= 100
            self.updated.emit(int(self.percent))
            time.sleep(0.1)

    def stop(self):
        self.running = False


class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, *args, **kwargs):
        super(MainWindow, self).__init__(*args, **kwargs)
        self.setupUi()

    def setupUi(self):
        self.setWindowTitle("Test")
        self.resize(446, 207)

        self.progressbar = QtWidgets.QProgressBar(self)
        self.progressbar.setGeometry(QtCore.QRect(40, 70, 381, 23))
        self.progressbar.setProperty("value", 0)

        self.btn_start = QtWidgets.QPushButton("Start", self)
        self.btn_start.setGeometry(QtCore.QRect(110, 110, 75, 23))
        self.btn_start.setEnabled(True)
        self.btn_start.clicked.connect(self.on_start)

        self.btn_stop = QtWidgets.QPushButton("Stop", self)
        self.btn_stop.setGeometry(QtCore.QRect(260, 110, 75, 23))
        self.btn_stop.setEnabled(False)
        self.btn_stop.clicked.connect(self.on_stop)

    def toggle_buttons(self):
        self.btn_start.setEnabled(not self.btn_start.isEnabled())
        self.btn_stop.setEnabled(not self.btn_stop.isEnabled())

    def on_update(self, data):
        self.progressbar.setValue(data)
#        if data == 99:
#            self.on_stop()

    def on_start(self):
        self.toggle_buttons()
        self.task = SlowTask(self)
        self.task.updated.connect(self.on_update)
        self.task.start()

    def on_stop(self):
        self.task.stop()
        self.progressbar.setValue(0)
        self.toggle_buttons()


if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    w = MainWindow()
    w.show()
    sys.exit(app.exec_())

def menu(request):
    return {'menu': MenuItems.objects.all()}

TEMPLATES = [
    {
        ...
        'OPTIONS': {
            'context_processors': [
                ...
                'mysite.context_processors.menu',
            ],
            ...
        }
    }
]

from subprocess import call
call(['notepad'])

import os
os.system('notepad')