and On Update / On Update after submit


I have a method that adds a child item to a doctype and then saves it (add_voucher_consumption).
The child item has the “on submit” enabled so that it can be triggered after the doc is submitted (I want this to be the case as I want to be able to consume submitted vouchers).

However, the of this function does not seem to trigger the update_after_submit or on update methods. For the moment my workaround is to trigger the function (check_voucher_consumption) at the end of my method but ideally it should be performed automatically whenever the submitted document is updated as specified in the controller methods.
I am not sure if this is a bug or not

class CustomerReferralVoucher(Document):

	def validate(self):

	def on_update_after_submit(self):

	def on_update(self):

	def check_voucher_consumption(self):
		voucher_value = self.voucher_value

		if not self.voucher_consumption:
			self.voucher_residual_value = voucher_value
			sum_value = sum(row.value for row in self.voucher_consumption)

			if sum_value == voucher_value:
				self.voucher_residual_value = 0
				self.status = "Depleted"

			elif sum_value < voucher_value:
				residual = voucher_value - sum_value
				self.voucher_residual_value = residual

				frappe.throw(_("Voucher Consumption ({0}) higher than voucher value of {1}").format(sum_value, voucher_value))
	def add_voucher_consumption(self,value):
		self.append('voucher_consumption', {
                'value': value,
				'date': today()})
		#self.check_voucher_consumption() >> ADDED as workaround