fix if there is no instance, it throws an error

fet2020/finance/forms.py

@@ -291,7 +291,8 @@ class ResolutionAdminForm(forms.ModelForm):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)  # to get the self.fields set
 
-        bills = Bill.objects.filter(resolution=kwargs["instance"])
+        resolution = kwargs.get("instance", None)
+        bills = Bill.objects.filter(resolution=resolution)
         total = 0
         for elem in bills:
             total += elem.amount
@@ -322,7 +323,8 @@ class WirefAdminForm(forms.ModelForm):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)  # to get the self.fields set
 
-        bills = Bill.objects.filter(wiref=kwargs["instance"])
+        wiref = kwargs.get("instance", None)
+        bills = Bill.objects.filter(wiref=wiref)
         total = 0
         for elem in bills:
             total += elem.amount