Django-guardian: DoNotExist: अनुमति मिलान क्वेरी मौजूद नहीं है।

जब भी मैं किसी पोस्ट के बाद अनुमतियां सेट करने का प्रयास करता हूं तो मेरे प्रोजेक्ट में मुझे DoNotExist त्रुटि मिलती है।

मेरे मॉडल.py

class Project(models.Model):
    # Leader of the project
    project_name = models.CharField(max_length=200, unique=True)

    # The url for the stash repository 
    #project_repo = models.

    # Date the project was created
    date_created = models.DateTimeField(auto_now=True)

    # Person in charge of the project
    project_lead = models.ForeignKey(User, related_name='%(class)s_lead_set')

    # Group of members to use for permission checking
    members = models.ForeignKey(Group, null=True, default=None)

    class Meta: 
        permissions = (
            ('edit_project', 'Edit Project'),
        )

मेरे विचार.py

<strong i="10">@login_required</strong>
def create(request): 
    if request.method== "POST": 
        form = NewProjectForm(request.POST)

        if form.is_valid(): 

            # Create the new project
            project = Project(**form.cleaned_data)
            project.project_lead = request.user

            # Create a user group
            members = Group.objects.create(name = project.project_name)
            members.save()

            # Add the members group to the project
            project.members = members
            project.save()

            assign_perm('edit', members, project)
            members.save()