forms.py

class emailforms(forms.ModelForm):
    email = forms.CharField(widget=forms.TextInput(attrs={'class': 'form-control'}),
                            max_length=200,
                            required=True,
                            )

    def clean(self):
        email_data=self.cleaned_data['email']
        try:
            match = Userdetails.objects.get(email=email_data)
        except:
            return self.cleaned_data.get('email')
        raise forms.ValidationError("already exis")
    class Meta:
            model=Userdetails
            fields=['email']