title: How to get previous data of model in forms
body: <p>How to get previous data of model <code>TrustyRequest</code> field <code>status</code>. I need previous data of <code>status field</code> because of this condition </p>
  
  <pre><code>if User.objects.filter(email=email).exists() and status=='Accepted':
  </code></pre>
  
  <p>I want to see the previous state of <code>status</code> field and compare with current status which is being update - <code>status=='Accepted'</code>. </p>
  
  <pre><code>class TrustyRequestForm(forms.ModelForm):
      class Meta:
          model = TrustyRequest
          fields = [
              'masjid_name', 
              'masjid_address', 
              'first_name', 
              'last_name', 
              'email', 
              'phone_number',
              'status',
          ]
  
      def clean(self):
          cleaned_data = super().clean()
          email = cleaned_data.get("email")
          status = cleaned_data.get("status")
  
          if User.objects.filter(email=email).exists() and status=='Accepted':
              raise forms.ValidationError("Email Already Exists")
  </code></pre>