use commit=True for default as django pattern, when we save or remove one model

ereuse_devicehub/inventory/forms.py

@@ -62,7 +62,7 @@ class LotDeviceForm(FlaskForm):
 
         return bool(self._devices)
 
-    def save(self):
+    def save(self, commit=True):
         trade = self._lot.trade
         if trade:
             for dev in self._devices:
@@ -73,11 +73,17 @@ class LotDeviceForm(FlaskForm):
             self._lot.devices.update(self._devices)
             db.session.add(self._lot)
 
-    def remove(self):
+        if commit:
+            db.session.commit()
+
+    def remove(self, commit=True):
         if self._devices:
             self._lot.devices.difference_update(self._devices)
             db.session.add(self._lot)
 
+        if commit:
+            db.session.commit()
+
 
 class LotForm(FlaskForm):
     name = StringField('Name', [validators.length(min=1)])

ereuse_devicehub/inventory/views.py

@@ -139,7 +139,7 @@ class LotDeviceAddView(View):
     def dispatch_request(self):
         form = LotDeviceForm()
         if form.validate_on_submit():
-            form.save()
+            form.save(commit=False)
             messages.success(
                 'Add devices to lot "{}" successfully!'.format(form._lot.name)
             )
@@ -159,7 +159,7 @@ class LotDeviceDeleteView(View):
     def dispatch_request(self):
         form = LotDeviceForm()
         if form.validate_on_submit():
-            form.remove()
+            form.remove(commit=False)
             messages.success(
                 'Remove devices from lot "{}" successfully!'.format(form._lot.name)
             )