chore: Handle edge cases

erpnext/accounts/doctype/tax_withholding_category/tax_withholding_category.py

@@ -437,8 +437,11 @@ def get_tds_amount(ldc, parties, inv, tax_details, tax_deducted, vouchers):
 
 def get_tcs_amount(parties, inv, tax_details, vouchers, adv_vouchers):
 	tcs_amount = 0
+	invoiced_amt = 0
+	advance_amt = 0
 
 	# sum of debit entries made from sales invoices
+	if vouchers:
 		invoiced_amt = (
 			frappe.db.get_value(
 				"GL Entry",
@@ -454,6 +457,7 @@ def get_tcs_amount(parties, inv, tax_details, vouchers, adv_vouchers):
 		)
 
 	# sum of credit entries made from PE / JV with unset 'against voucher'
+	if advance_amt:
 		advance_amt = (
 			frappe.db.get_value(
 				"GL Entry",