title: TypeError: unsupported operand type(s) for -: 'datetime.time' and 'datetime.time'
body: <p>my models.py:</p>
  
  <pre><code>class Attendancename(models.Model):
      teacher_name = models.ForeignKey(Teachername, default='Ram')
      date = models.DateField('Date', default=datetime.datetime.today)
      intime = models.TimeField('IN-TIME', auto_now=True)
      outtime = models.TimeField('OUT-TIME', auto_now=True)
  
      def hours_conversion(self):
          startdelta = datetime.timedelta(hours=self.intime.hours, minutes=self.intime.minutes, seconds=self.intime.seconds)
          enddelta = datetime.timedelta(hours=self.outtime.hours, minutes=self.outtime.minutes, seconds=self.outtime.seconds)
          return (enddelta-startdelta).seconds/3600
  
      def __str__(self):
          return "%s" %self.teacher_name
  </code></pre>
  
  <p>my views.py:</p>
  
  <pre><code>def add_atten(request):
      if request.method == 'POST':
          form = AttendancenameForm(request.POST)
          if form.is_valid():
              form.save()
              return HttpResponseRedirect(reverse('student:listatten'))
          else:
              print(form.errors)
      else:       
          form = AttendancenameForm()
      return render(request, 'add_atten.html', {'form': form},)
  </code></pre>
  
  <p>my forms.py:</p>
  
  <pre><code>class AttendancenameForm(ModelForm):
      intime = forms.TimeField(input_formats=('%H:%M',))
      outtime = forms.TimeField(input_formats=('%H:%M',))
      teacher_name = forms.ModelChoiceField(queryset=Teachername.objects.all())
      class Meta:
          model = Attendancename
          fields = ('teacher_name', 'date', 'intime', 'outtime',)
  </code></pre>
  
  <p>Actually I'm trying to calculate total number of hours based on difference of <code>'intime'</code> and <code>'outtime'</code> in my models.py file but it raises above erroe. I think I'm doing syntax error. Can anybody Please tell me what is the correct syntax or method to do so?
  Any body please suggest me what to do to fix it?</p>