Error message in the form when the voucher is invalid

lostplaces/lostplaces_app/forms.py

@@ -8,42 +8,43 @@ from django.contrib.auth.forms import UserCreationForm, UserChangeForm
 from .models import Explorer, Place, PlaceImage, Voucher
 
 class ExplorerCreationForm(UserCreationForm):
-    class Meta:
-        model = Explorer
-        fields = ('username', 'email')
-    voucher = forms.CharField(max_length=10, help_text='The Voucher you got from an administrator')
+	class Meta:
+		model = Explorer
+		fields = ('username', 'email')
+	voucher = forms.CharField(max_length=10, help_text='The Voucher you got from an administrator')
 
-    def is_valid(self):
-        super().is_valid()
-        sumitted_voucher = self.cleaned_data.get('voucher')
-        try:
-            fetched_voucher = Voucher.objects.get(code=sumitted_voucher)
-        except Voucher.DoesNotExist:
-            return False
+	def is_valid(self):
+		super().is_valid()
+		sumitted_voucher = self.cleaned_data.get('voucher')
+		try:
+			fetched_voucher = Voucher.objects.get(code=sumitted_voucher)
+		except Voucher.DoesNotExist:
+			self.add_error('voucher', 'Invalid voucher')
+			return False
 
-        fetched_voucher.delete()
-        return True
+		fetched_voucher.delete()
+		return True
 
 class ExplorerChangeForm(UserChangeForm):
-    class Meta:
-        model = Explorer
-        fields = ('username', 'email')
+	class Meta:
+		model = Explorer
+		fields = ('username', 'email')
 
 class PlaceForm(forms.ModelForm):
-    class Meta:
-        model = Place
-        fields = '__all__'
-        exclude = ['submitted_by']
-        
+	class Meta:
+		model = Place
+		fields = '__all__'
+		exclude = ['submitted_by']
+		
 class PlaceImageCreateForm(forms.ModelForm):
-    class Meta:
-        model = PlaceImage
-        fields = ['filename']
-        widgets = {
-            'filename': forms.ClearableFileInput(attrs={'multiple': True})
-        }
+	class Meta:
+		model = PlaceImage
+		fields = ['filename']
+		widgets = {
+			'filename': forms.ClearableFileInput(attrs={'multiple': True})
+		}
 
-    def __init__(self, *args, **kwargs):
-        super().__init__(*args, **kwargs)
+	def __init__(self, *args, **kwargs):
+		super().__init__(*args, **kwargs)
 
-        self.fields['filename'].required = False
+		self.fields['filename'].required = False