how to custom user model with groups in django code example

Example 1: django add user to group

from django.contrib.auth.models import Group, User
tonystark=User.objects.get(id=pk)
hulk=Group.objects.get(name='groupname')
hulk.user_set.add(tonystark)

Example 2: django add user to group

from django.contrib.auth.models import Group
my_group = Group.objects.get(name='my_group_name') 
my_group.user_set.add(your_user)