Lead.objects.create(first_name="Linh", last_name="Le", age=25, agent=admin@gmail.com)
Lead.objects.all()
Lead.objects.filter(first_name="Linh")
Lead.objecs.filter(age__gt=20)
Agent.objects.get(user__email="admin@gmail.com") Agent.objects.get(user=1) = Agent.objects.get(user__id=1)
Lead.objects.get(agent=1) = Lead.objects.get(agent__user=1)