/during i apply an old tutorial for social media site clone i found this problem and here is the details of my project
frist my models.py file/

`from django.db import models


from django.utils.text import slugify
import misaka
from django import template
from django.contrib.auth import get_user_model
from django.urls import reverse

User = get_user_model()
register = template.Library()


class Group(models.Model):
    name = models.CharField(max_length=255, unique=True)
    slug = models.SlugField(allow_unicode=True, unique=True)
    description = models.TextField(blank=True, default='')
    description_html = models.TextField(editable=False, default='', blank=True)
    members = models.ManyToManyField(User, through='GroupMember')

    def __str__(self):
        return self.name

    def save(self, *args, **kwargs):
        self.slug = slugify(self.name)
        self.description_html = misaka.html(self.description)
        super().save(*args, **kwargs)

    def get_absolute_url(self):
        return reverse('groups:single', kwargs={'slug': self.slug})

    class Meta:
        ordering = ['name']


class GroupMember(models.Model):
    group = models.ForeignKey(Group, related_name='memberships', on_delete=models.CASCADE)
    user = models.ForeignKey(User, related_name='user_groups', on_delete=models.CASCADE)

    def __str__(self):
        return self.user.username

    class Meta:
        unique_together = ('group', 'user')`

/then my urls.py/

`from django.urls import path
 from . import views
 app_name='groups'
 urlpatterns=[
    path('',views.ListGroups.as_view(),name='all'),
    path('new/',views.CreateGroup.as_view(),name='create'),
    path('post/in/<slug>/',views.SingleGroup.as_view(),name='single'),
    path('join/<slug>/',views.JoinGroup.as_view(),name='join'),
    path('leave/<slug>/',views.LeaveGroup.as_view(),name='leave'),
]
`

/*and this is my views.py belong myapp*/

from django.contrib.auth.mixins import LoginRequiredMixin,PermissionRequiredMixin
from django.urls import reverse
from django.contrib import messages
from django.shortcuts import get_object_or_404
from django.views.generic import CreateView,DetailView,ListView,RedirectView
from .models import Group,GroupMember
from . import models
class CreateGroup(LoginRequiredMixin,CreateView):
    fields=('name','description')
    model=Group
class SingleGroup(DetailView):
    model=Group
class ListGroups(ListView):
    model = Group


class JoinGroup(LoginRequiredMixin,RedirectView):
    def get_redirect_url(self, *args, **kwargs):
        return reverse('groups:single',self.kwargs.get('slug'))
    def get(self, request, *args, **kwargs):
        group=get_object_or_404(Group,slug=self.kwargs.get('slug'))
        try:
            GroupMember.objects.create(user=self.request.user,group=group)
        except:
            messages.warning(self.request,('warning already a member'.title()))
        else:
            messages.success(self.request,('you are now a member'.title()))
        return super().get(request,*args,**kwargs)





class LeaveGroup(LoginRequiredMixin,RedirectView):
    def get_redirect_url(self, *args, **kwargs):
        return reverse('groups:single',self.kwargs.get('slug'))
    def get(self, request, *args, **kwargs):
        try:
            membership=models.GroupMember.objects.filter(
                user=self.request.user,
                group__slug=self.kwargs.get('slug')
            ).get()
        except models.GroupMember.DoesNotExist:
            messages.warning(self.request,('sorry you aren't in this group'.title()))
        else:
            membership.delete()
            messages.success(self.request,'you have left the group!'.title())
            return super().get(request,*args,**kwargs)

/and it tells me that the problem in this 2 codes*/

`return super().get(request,*args,**kwargs)  

return reverse('groups:single',self.kwargs.get('slug'))

so please help sure science-group is agroup that i created after slugify the name of the group science group

so please help