fix(Sales Invoice): Let invoice be created for Sold Assets if it's a return invoice
diff --git a/erpnext/accounts/doctype/sales_invoice/sales_invoice.py b/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
index a008742..c835deb 100644
--- a/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
+++ b/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
@@ -149,7 +149,7 @@
 					if self.update_stock:
 						frappe.throw(_("'Update Stock' cannot be checked for fixed asset sale"))
 
-					elif asset.status in ("Scrapped", "Cancelled", "Sold"):
+					elif asset.status in ("Scrapped", "Cancelled") or asset.status == "Sold" and not self.is_return:
 						frappe.throw(_("Row #{0}: Asset {1} cannot be submitted, it is already {2}").format(d.idx, d.asset, asset.status))
 
 	def validate_item_cost_centers(self):