How to insert multiple choices in to the database and display - django

Question

My models is:
class LabRequest(models.Model):
ticket = models.ForeignKey(Ticket, on_delete=models.CASCADE)
lab_test = models.ManyToManyField(Lab)
My Form
class LabRequestModelForm(forms.ModelForm):
class Meta:
model = LabRequest
fields = ['ticket', 'lab_test']
widgets = {
'lab_test': forms.CheckboxSelectMultiple,
}
My view
def LabRequestToGenerateView(request):
if form.is_valid():
obj = form.save(commit=False)
obj.created_by = request.user.id
obj.save()
return render(request, 'dashboard/laboratory_request.html', {'form': form})
My Template
<form action="." method="POST">
{% csrf_token %}
{{ form.as_p }}
<div class="form-group float-right">
<button type="submit" name="submit" class="btn btn-success btn-sm" > <i
class="fa fa-save"></i>
Save</button>
</div>
</form>
{% for rl in rl %}
<label for=""> Ticket: {{ rl.ticket }} </label>
<p> Lab Tests: {{ rl.lab_test }}</p>
{% endfor %}
So, It's displaying as a checkbox that's good. but when i want to save some data it saves only ticket, not lab_test? So, how do I save both?
As you see it displays only ticket which is Ubed Gedi ALi and where I wanted to see lab_test it shows me appname.modelname.None