Error uploading file in django - django

Question

I am trying to attach a file in django models, but when I hit submit button the selected file immediately disappears and the form submission fails . What is going wrong here?
forms.py
from django import forms
from .models import IssueNotice
class IssueNoticeForm(forms.ModelForm):
class Meta:
model = IssueNotice
fields = ('title', 'content','issuer','attachment',)
models.py
from django.db import models
from django.utils import timezone
from django import forms
class IssueNotice(models.Model):
title = models.CharField(max_length=300)
content = models.TextField()
attachment = models.FileField(upload_to='attachments')
issuer = models.CharField(max_length=100)
issuer_id = models.ForeignKey('auth.User')
issued_date = models.DateTimeField(default = timezone.now)
def publish(self):
self.issued_date = timezone.now()
self.save()
def __str__(self):
return self.title
views.py
from django.shortcuts import render
from django.utils import timezone
from django.shortcuts import redirect
from django.contrib.auth.decorators import login_required
from .models import IssueNotice
from .forms import IssueNoticeForm
def issue_notice(request):
if request.method == "POST":
form = IssueNoticeForm(request.POST, request.FILES)
if form.is_valid():
handle_uploaded_file(request.FILES['attachment'])
notice = form.save(commit = False)
notice.issuer_id = request.user
notice.issued_date = timezone.now()
notice.save()
return redirect('home_page')
else:
form = IssueNoticeForm()
return render(request, 'webadmin/issue_notice.html',{'form':form})
issue_notice.html
{% extends 'webadmin/base.html' %}
{% block content %}
<div class="col-md-8">
<form method="POST" class="post-form">{% csrf_token %}
{{ form.as_p }}
<button type="submit" class="save btn btn-default">Issue</button>
</form>
{% endblock %}